Which of the following is an example of vegetative propagation?

Growing new plants from Bryophyllum leaves

The testes are located outside the abdominal cavity in the scrotum because:

Sperm formation requires a lower temperature.

It provides more space for growth.

Why is variation useful for the survival of species over time?

It allows some individuals to survive drastic environmental changes.

It makes all individuals identical.

It helps in rapid population decline.

It allows some individuals to survive drastic environmental changes.

It ensures that all organisms are equally susceptible to diseases.

Which of the following is NOT an advantage of vegetative propagation?

It introduces significant genetic variation in offspring.

Plants raised can bear flowers and fruits earlier.

It allows propagation of plants that have lost the capacity to produce seeds.

It introduces significant genetic variation in offspring.

All plants produced are genetically similar to the parent plant.

Why is the sexual mode of reproduction considered advantageous over the asexual mode in terms of generating variation?

It combines variations from two different individuals.

It ensures exact copies of DNA are made.

It combines variations from two different individuals.

It is a much faster process than asexual reproduction.

It prevents any mutations from occurring.

What is the primary function of the seminal vesicles and the prostate gland in the male reproductive system?

To add secretions that make sperm transport easier and provide nutrition.

Assertion (A): Regeneration is not the same as reproduction. Reason (R): Most organisms would not normally depend on being cut up to be able to reproduce.

A and R both correct, R explains A

Assertion (A): The male germ-cell is motile and the female germ-cell contains stored food. Reason (R): This specialisation helps in efficient fusion and provides initial nourishment to the zygote.

A and R both correct, R explains A

A farmer wants to grow banana plants that are genetically identical to a high-yielding parent plant and also bear fruits earlier than those grown from seeds. Which of the following methods would be most suitable?

Using vegetative propagation methods like layering or tissue culture.

Growing from seeds produced by sexual reproduction.

Using vegetative propagation methods like layering or tissue culture.

Allowing cross-pollination between different banana varieties.

Encouraging spore formation from the parent plant.

A couple is concerned about preventing both pregnancy and sexually transmitted infections (STIs). Which contraceptive method would be most effective for their needs?

Surgical methods (vasectomy/tubectomy)

Which of the following statements about the process shown in the diagram is/are correct?

The new individuals are genetically identical to the parent.

It represents sexual reproduction.

The new individuals are genetically identical to the parent.

It is a characteristic of complex multicellular organisms.

It involves the fusion of gametes.

Observe the diagram showing spore formation in Rhizopus. What is the significance of the thick walls covering the spores?

They protect the spores from unfavorable conditions.

They aid in the dispersal of spores by wind.

They provide nutrition for the growing hyphae.

Which of the following statements are true regarding sexual reproduction in human beings? Select all that apply.

The embryo gets nourishment from the mother's blood via the placenta.

Fertilisation usually occurs in the uterus.

The embryo gets nourishment from the mother's blood via the placenta.

Sperm formation requires a temperature higher than normal body temperature.

The development of the child inside the mother's body takes approximately nine months.

Which of the following are benefits of practicing vegetative propagation for certain plants? Select all that apply.

Plants raised can bear flowers and fruits earlier.

It helps in producing plants with genetic variations.

Plants raised can bear flowers and fruits earlier.

It enables propagation of plants that have lost the capacity to produce seeds.

It makes plants more resistant to all types of diseases.

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Absolutely! All questions are meticulously aligned with the NCERT Class 10 Science textbook for Chapter 7, ensuring relevance to your CBSE curriculum.

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The quiz covers all major topics from Chapter 7, including DNA copying, asexual reproduction (fission, budding, fragmentation, regeneration, vegetative propagation, spore formation), sexual reproduction in plants and humans, and reproductive health.

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Home › CBSE › Class 10 › Science › How do Organisms Reproduce?

CBSE · Class 10 · 🔬 Science · Chapter 7

How do Organisms Reproduce?

DNA copying and variationAsexual reproduction modesSexual reproduction in plantsHuman male reproductive systemHuman female reproductive systemMenstruation

This chapter introduces students to the fundamental biological process of reproduction, explaining why it is essential for the survival of species. It delves into the mechanisms of DNA copying and the importance of variation. The chapter covers various modes of asexual reproduction in single and multi-cellular organisms, including fission, fragmentation, regeneration, budding, vegetative propagation, and spore formation. It then transitions to sexual reproduction, highlighting its advantages and detailing the processes in flowering plants and human beings, including reproductive health and contraception. Understanding these concepts is crucial for building a strong foundation in biology.

Reproduction: DNA Copying aur Variation

Har organism apne jaise naye individuals banata hai, is process ko reproduction kehte hain. Ye life maintain karne ke liye zaruri nahi, but species ki continuity ke liye essential hai.

DNA Copying: Reproduction ka basic level hai DNA ki copies banana.
Cell nucleus mein chromosomes hote hain, jinmein DNA (Deoxyribo Nucleic Acid) hota hai.
DNA mein information hoti hai jo parents se next generation mein features transfer karti hai.
DNA cell ke liye proteins banane ka source hai. Agar DNA change ho, toh different proteins banenge, leading to altered body designs.
Reproduction mein, cells chemical reactions use karke DNA ki copies banate hain.
Ek reproducing cell mein do DNA copies banti hain, aur har copy ko apna cellular apparatus milta hai. Isse ek cell do cells mein divide ho jata hai.

Variation during DNA Copying:
DNA copying process 100% accurate nahi hota. Biochemical reactions mein errors ho sakte hain.
Isliye, jo naye DNA copies bante hain, wo original se similar hote hain, but identical nahi.
Ye small differences ko variation kehte hain.
Kuch variations itne drastic ho sakte hain ki naya cell survive na kar paye.
Lekin, jo variations survive karte hain, wo species ke liye beneficial hote hain.

Importance of Variation:
Organisms specific niches mein rehte hain aur reproduce karte hain.
DNA copying ki consistency body design features maintain karti hai, jo unhe us niche mein rehne mein help karti hai.
Lekin, niches change ho sakte hain (e.g., temperature, water levels).
Agar ek population ek particular niche ke liye suited hai aur wo niche drastically change ho jaye, toh puri population wipe out ho sakti hai.
Variation hi survival ki guarantee hai. Agar kuch individuals mein variations honge jo unhe changed conditions mein survive karne mein help karein, toh wo species continue kar payegi.
Example: Agar bacteria ki population temperate waters mein rehti hai aur global warming se temperature badh jaye, toh most bacteria mar jayenge. Lekin, jin bacteria mein heat resistance ka variation hoga, wo survive karke grow karenge. Is tarah, variation species ke survival ke liye bahut zaruri hai (basis of evolution).

❗Important

DNA ka Role: DNA mein genetic information hoti hai jo parents se offspring mein jati hai. Ye reproduction ka fundamental aspect hai.

💡Tip

Variation ka concept bahut important hai. Iska link evolution se bhi hai (next chapter mein padhenge). Question aa sakta hai: 'Why is variation important for the survival of a species?'

Asexual Reproduction: Single Parent Se Naye Jeev

Asexual reproduction mein sirf ek parent involve hota hai aur offspring genetically identical hote hain parent ke. Ye unicellular aur simple multicellular organisms mein common hai.

2.1 Fission (Vibhajana)

Definition: Unicellular organisms mein cell division, jisse naye individuals bante hain.
Types:
Binary Fission (Dwivibhajana):
Parent cell do equal halves mein split hota hai.
Nucleus pehle divide hota hai, fir cytoplasm.
Examples:
Amoeba: Irregular shape ki wajah se splitting kisi bhi plane mein ho sakti hai. [IMAGE: TODO: Diagram of Binary fission in Amoeba]
Leishmania (Kala-azar ka causative agent): Isme whip-like structure (flagellum) hota hai, isliye fission definite orientation mein hota hai. [IMAGE: TODO: Diagram of Binary fission in Leishmania]
Multiple Fission (Bahuvibhajana):
Parent cell ek saath many daughter cells mein divide hota hai.
Nucleus repeatedly divide hota hai, fir cytoplasm divide hota hai, aur har nucleus ko thoda cytoplasm milta hai.
Example: Plasmodium (Malarial parasite). [IMAGE: TODO: Diagram of Multiple fission in Plasmodium]

2.2 Fragmentation (Khandan)

Definition: Simple multicellular organisms mein, body parts mein break ho jati hai, aur har fragment naye individual mein grow karta hai.
Conditions: Sirf un organisms mein jinka body organization simple hota hai, jahan specialized tissues aur organs ka complex arrangement nahi hota.
Example: Spirogyra (ek type ki algae). Mature hone par, Spirogyra filaments chote pieces mein toot jaate hain, aur har piece naya Spirogyra banata hai.
Note: Ye complex multicellular organisms mein possible nahi hai, kyunki unki body mein cells specialized hote hain aur specific locations par arranged hote hain.

2.3 Regeneration (Punarnirman)

Definition: Fully differentiated organisms ki ability ki wo apne cut ya broken body parts se naye individual organisms bana sakein.
Mechanism: Specialized cells proliferate (rapidly divide) karte hain aur large number of cells banate hain. Fir ye cells differentiate hoke various cell types aur tissues banate hain, jisse poora organism develop hota hai.
Examples: Hydra aur Planaria. Agar Planaria ko kai pieces mein kaat diya jaye, toh har piece ek complete Planaria mein develop ho jata hai. [IMAGE: TODO: Diagram of Regeneration in Planaria]
Important Point: Regeneration reproduction jaisa nahi hai. Most organisms normally cut hoke reproduce nahi karte. Ye ek repair mechanism zyada hai, jisse naye individuals bhi ban sakte hain.

2.4 Budding (Mukulana)

Definition: Parent body par ek outgrowth (bud) develop hota hai due to repeated cell division at one specific site. Ye bud grow karke naya individual banta hai aur mature hone par parent se detach ho jata hai.
Examples:
Hydra: Body par ek chota bud banta hai, jo grow karke naya Hydra banata hai aur alag ho jata hai. [IMAGE: TODO: Diagram of Budding in Hydra]
Yeast: Unicellular fungus, jismein bhi budding hoti hai. [IMAGE: TODO: Diagram of Budding in Yeast]

2.5 Vegetative Propagation (Kayik Pravardhan)

Definition: Plants mein reproduction ka method jahan roots, stems, aur leaves jaise vegetative parts se naye plants develop hote hain.
Advantages:
Plants jaldi flowers aur fruits bear karte hain, seeds se grow kiye hue plants ke comparison mein.
Un plants ko propagate karna possible hai jinhone seeds produce karne ki capacity kho di hai (e.g., banana, orange, rose, jasmine).
Naye plants genetically identical hote hain parent plant ke, isliye unke saare desired characteristics retain hote hain.
Methods:
Natural Methods:
Stems: Potato (eyes/buds), Ginger (rhizome), Onion (bulb).
Leaves: Bryophyllum (leaf margins par buds). Ye buds soil par girkar naye plants banate hain. [IMAGE: TODO: Diagram of Leaf of Bryophyllum with buds]
Roots: Dalhia, Sweet potato.
Artificial Methods (Agricultural use):
Layering: Branch ko bend karke soil mein daba dete hain, roots develop hone par cut karke naya plant banate hain.
Grafting: Do different plants ke parts ko join karte hain (stock aur scion) to grow as one plant.
Cutting: Stem ke pieces ko soil mein lagate hain (e.g., rose, sugarcane).

2.6 Spore Formation (Beejanu Nirman)

Definition: Organisms mein reproduction ka method jahan spores produce hote hain, jo unfavorable conditions mein survive kar sakte hain aur favorable conditions mein naye individuals mein grow karte hain.
Mechanism: Spores thick walls se covered hote hain jo unhe protect karti hain. Jab unhe moist surface milti hai, toh wo germinate karke naye organism banate hain.
Example: Rhizopus (Bread mould). Bread mould mein thread-like hyphae hote hain. Reproductive parts 'blob-on-a-stick' structures hote hain jinhe sporangia kehte hain. Sporangia ke andar spores hote hain. [IMAGE: TODO: Diagram of Spore formation in Rhizopus]

🚧Misconception

Regeneration aur Fragmentation mein confusion. Fragmentation simple multicellular mein body ka break hona hai. Regeneration mein specialized cells se poora naya organism banta hai, even from a small piece.

💡Tip

Vegetative propagation ke advantages bahut important hain for board exams. Direct question aata hai.

Sexual Reproduction: Do Parents Ka Sangam

Sexual reproduction mein do individuals (male aur female) involve hote hain naye generation ko create karne ke liye. Isse variation zyada aati hai.

3.1 Why Sexual Reproduction?

Variation ka Source: DNA copying mein errors se variations aate hain, but ye slow process hai. Sexual reproduction do different individuals ke DNA ko combine karta hai, jisse naye combinations of variants bante hain aur variation ka process speed up hota hai.
Survival Advantage: Zyada variations hone se species ko changing environment mein adapt aur survive karne ka behtar chance milta hai.
Chromosome Number Maintenance: Agar do individuals ke cells directly fuse ho jayein, toh har generation mein chromosome number double ho jayega. Is problem ko solve karne ke liye, sexual reproduction mein specialized germ-cells (gametes) bante hain.
Ye germ-cells meiosis naam ke cell division process se bante hain, jismein chromosome number half ho jata hai (haploid, n).
Jab male aur female gametes fuse karte hain (fertilization), toh diploid (2n) zygote banta hai, jisse chromosome number restore ho jata hai.
Gamete Specialization: Complex organisms mein, gametes bhi specialized hote hain:
Female Gamete (Egg/Ovum): Large, non-motile, aur food-stores contain karta hai embryo ke initial development ke liye.
Male Gamete (Sperm): Smaller, motile, aur genetic material carry karta hai.

3.2 Sexual Reproduction in Flowering Plants

Flower: Reproductive Organ: Angiosperms (flowering plants) mein reproductive parts flower mein hote hain. [IMAGE: TODO: Longitudinal section of flower]
Flower ke Parts:
Sepals: Green, leaf-like structures, flower ko bud stage mein protect karte hain.
Petals: Brightly coloured, insects ko attract karte hain for pollination.
Stamen (Male Reproductive Part): Consists of:
Anther: Pollen grains produce karta hai (yellowish powder).
Filament: Anther ko support karta hai.
Pistil/Carpel (Female Reproductive Part): Center mein hota hai, consists of:
Stigma: Sticky, pollen grains receive karta hai.
Style: Elongated tube, stigma aur ovary ko connect karta hai.
Ovary: Swollen bottom part, ovules contain karta hai. Har ovule mein ek egg cell hota hai.
Flower Types:
Unisexual Flower: Sirf stamen ya sirf pistil hota hai (e.g., Papaya, Watermelon).
Bisexual Flower: Dono stamen aur pistil hote hain (e.g., Hibiscus, Mustard).
Pollination: Pollen grains ka anther se stigma tak transfer.
Self-pollination: Pollen transfer same flower mein ya same plant ke do flowers ke beech.
Cross-pollination: Pollen transfer ek flower se dusre plant ke flower tak.
Agents of Pollination: Wind, water, insects, animals.
Fertilization: Pollen grain stigma par land hone ke baad, ek pollen tube grow karta hai style ke through ovary tak. Male germ-cell (pollen grain se) female gamete (egg cell in ovule) se fuse karta hai. Is fusion ko fertilization kehte hain.
Post-Fertilization Changes:
Zygote: Fertilized egg, jo multiple times divide hoke embryo banata hai.
Ovule: Embryo ke saath tough coat develop karke seed mein convert ho jata hai.
Ovary: Rapidly grow karke fruit mein ripen ho jata hai.
Seed: Future plant (embryo) contain karta hai. Favorable conditions mein seed germinate hoke seedling banata hai (process ko germination kehte hain). [IMAGE: TODO: Diagram of Germination]

3.3 Reproduction in Human Beings

Puberty: Adolescence ka period jab reproductive tissues mature hona shuru karte hain. Is time body mein kai changes aate hain (secondary sexual characteristics).
Common changes (boys & girls): Armpits aur genital area mein thick hair growth, skin oily hona, pimples.
Girls mein changes: Breast size increase, nipples ka darkening, menstruation start hona.
Boys mein changes: Face par thick hair growth (beard, mustache), voice crack hona, penis ka enlargement aur erection.
Male Reproductive System:
Testes (Vrishan): Primary male reproductive organ.
Location: Abdominal cavity ke bahar scrotum mein located, kyunki sperm formation ke liye lower temperature chahiye normal body temperature se.
Function: Sperms (male germ-cells) produce karna aur testosterone hormone secrete karna (sperm formation regulate karta hai aur puberty changes lata hai).
Vas Deferens: Sperms ko testes se urethra tak carry karta hai.
Seminal Vesicles & Prostate Gland: Vas deferens ke path mein secretions add karte hain.
Ye secretions fluid medium provide karte hain sperms ko transport ke liye.
Ye fluid nutrition bhi provide karta hai sperms ko.
Urethra: Common passage for both sperms aur urine.
Penis: External male organ, sperms ko female reproductive tract mein deliver karta hai.
Sperms: Tiny bodies, mainly genetic material aur ek long tail hoti hai jo movement mein help karti hai. [IMAGE: TODO: Human–male reproductive system]
Female Reproductive System:
Ovaries (Andashay): Primary female reproductive organ.
Location: Abdominal cavity mein.
Function: Eggs (female germ-cells/ova) produce karna aur female hormones (estrogen, progesterone) produce karna.
Birth ke time hi thousands of immature eggs hote hain. Puberty par, eggs mature hona shuru hote hain. Har month ek ovary ek egg release karti hai.
Oviducts/Fallopian Tubes: Thin tubes jo egg ko ovary se uterus tak carry karte hain. Fertilization yahi par hota hai.
Uterus (Garbhashay): Elastic, bag-like structure jahan fertilized egg implant hota hai aur embryo develop karta hai.
Cervix: Uterus ka lower narrow part jo vagina mein open hota hai.
Vagina: Muscular tube jo cervix se body ke bahar tak extend karta hai. Sperms yahi se enter karte hain during sexual intercourse.
Fertilization & Implantation: Sperms vagina se travel karke oviduct tak pahunchte hain. Agar egg present ho, toh fertilization oviduct mein hota hai. Fertilized egg (zygote) divide hoke ball of cells (embryo) banata hai. Embryo uterus ki lining mein implant ho jata hai.
Embryo Development: Uterus har month khud ko prepare karta hai embryo ko receive aur nurture karne ke liye. Lining thick aur spongy ho jati hai, blood supply rich ho jati hai.
Placenta: Special tissue jo disc-shaped hota hai aur uterine wall mein embedded hota hai.
Function: Embryo ko mother ke blood se nutrition (glucose, oxygen) provide karta hai aur waste substances ko mother ke blood mein transfer karta hai.
Development period approx 9 months hota hai. Child birth uterus ke muscles ke rhythmic contractions se hota hai. [IMAGE: TODO: Human–female reproductive system]
What happens when the Egg is not Fertilized? (Menstruation):
Agar egg fertilize nahi hota, toh wo approx 1 din tak alive rehta hai.
Uterus har month khud ko prepare karta hai fertilized egg ke liye, isliye uski lining thick aur spongy ho jati hai.
Agar fertilization nahi hota, toh ye thick lining ki zarurat nahi rehti.
Toh, ye lining break ho jati hai aur blood aur mucous ke form mein vagina se bahar nikal jati hai. Is process ko menstruation kehte hain.
Ye cycle roughly har month hota hai aur 2 se 8 din tak rehta hai.
Reproductive Health:
Sexual maturation ka matlab ye nahi ki body aur mind sexual acts ya parenting ke liye ready hain.
Sexually Transmitted Diseases (STDs): Sexual act se kai diseases transmit ho sakti hain, kyunki ye intimate connection hai.
Bacterial STDs: Gonorrhoea, Syphilis.
Viral STDs: Warts, HIV-AIDS.
Prevention: Condoms use karna transmission ko kuch had tak prevent karta hai.
Contraception (Pregnancy rokne ke tareeke): Unwanted pregnancy avoid karne ke liye methods.
Mechanical Barriers: Sperms ko egg tak pahunchne se rokte hain.
Condoms: Penis par use hote hain.
Diaphragm/Cervical caps: Vagina mein use hote hain.
Chemical Methods (Oral Contraceptive Pills):
Hormonal balance change karte hain, jisse eggs release nahi hote aur fertilization nahi hota.
Side effects ho sakte hain.
Intrauterine Contraceptive Devices (IUCDs):
Loop, Copper-T: Uterus mein place kiye jaate hain pregnancy rokne ke liye.
Uterus mein irritation se side effects ho sakte hain.
Surgical Methods: Permanent methods.
Vasectomy (Males): Vas deferens ko block ya cut karte hain, sperm transfer ruk jata hai.
Tubectomy (Females): Fallopian tubes ko block ya cut karte hain, egg uterus tak nahi pahunch pata aur fertilization nahi hota.
Ye methods long run mein safe hain, but surgery ke apne risks hote hain (infection, complications).
Social Concerns: Sex-selective abortion (female foeticide) ek serious issue hai, jisse child sex ratio disturb hota hai. Prenatal sex determination law dwara prohibited hai.
Population Control: Human population size bhi ek concern hai, kyunki expanding population se standard of living improve karna mushkil ho jata hai. Contraceptive methods population control mein help karte hain.

❗Important

Meiosis ka role yaad rakho! Ye chromosome number ko half karta hai gametes mein, jisse fertilization ke baad species ka chromosome number maintain rehta hai.

💡Tip

Flowering plants mein pollination aur fertilization ke steps, aur human reproductive systems ke labelled diagrams bahut common hain board exams mein. Functions bhi yaad rakhna.

🚧Misconception

Placenta aur Umbilical Cord mein confusion. Placenta uterine wall mein embedded tissue hai jo exchange karta hai. Umbilical cord wo tube hai jo baby ko placenta se connect karti hai.

⭐Remember

Contraceptive methods ke types aur unke working principles ko ache se prepare karna. STDs ke examples bhi.

Easy (15)

Which of the following is the basic event in reproduction?
- Cell growth
- Creation of a DNA copy (correct)
- Protein synthesis
- Tissue differentiation
Why: DNA copying is fundamental for passing genetic information.
The process of cell division in unicellular organisms, leading to new individuals, is called:
- Budding
- Fragmentation
- Fission (correct)
- Regeneration
Why: Fission is the primary mode of reproduction in unicellular organisms.
Which part of a flower produces pollen grains?
- Ovary
- Stigma
- Anther (correct)
- Petal
Why: The anther is the male reproductive part that contains pollen.
The fusion of male and female germ-cells is called:
- Pollination
- Germination
- Fertilisation (correct)
- Meiosis
Why: Fertilisation is the key event that forms a zygote.
Which of the following is a sexually transmitted bacterial infection?
- HIV-AIDS
- Warts
- Gonorrhoea (correct)
- Common cold
Why: Gonorrhoea is listed as a bacterial sexually transmitted infection.
The process by which an embryo gets nourishment from the mother's blood is through a special tissue called:
- Uterus lining
- Oviduct
- Placenta (correct)
- Cervix
Why: The placenta provides glucose and oxygen to the embryo and removes waste.
Which of the following is an example of vegetative propagation?
- Spore formation in Rhizopus
- Budding in Hydra
- Growing new plants from Bryophyllum leaves (correct)
- Binary fission in Amoeba
Why: Bryophyllum leaves with buds are a classic example of vegetative propagation.
The testes are located outside the abdominal cavity in the scrotum because:
- It protects them from injury.
- Sperm formation requires a lower temperature. (correct)
- It helps in hormone secretion.
- It provides more space for growth.
Why: Sperm production needs a temperature lower than normal body temperature.
DNA copying is an absolutely reliable process without any variations.
Why: DNA copying is not absolutely reliable and introduces variations.
Regeneration is the same as reproduction, as organisms normally depend on being cut up to reproduce.
Why: Regeneration is not a primary mode of reproduction for most organisms.
The transfer of pollen from one flower to another is known as self-pollination.
Why: Transfer of pollen between different flowers is cross-pollination.
The information source for making proteins in a cell nucleus is the _______ molecules.
Why: DNA contains the instructions for protein synthesis.
Organisms like Hydra reproduce asexually by forming an outgrowth called a ______.
Why: Hydra reproduces by budding, where a new individual grows from an outgrowth.
Identify the part labeled 'A' in the given diagram of a flower.
- Petal
- Sepal
- Stigma
- Anther (correct)
Why: Part A points to the anther, which produces pollen.
Which part of the human male reproductive system is indicated by 'X'?
- Vas deferens
- Testis (correct)
- Urethra
- Prostate gland
Why: X indicates the testis, where sperm are produced.

Medium (15)

Why is variation useful for the survival of species over time?
- It makes all individuals identical.
- It helps in rapid population decline.
- It allows some individuals to survive drastic environmental changes. (correct)
- It ensures that all organisms are equally susceptible to diseases.
Why: Variation provides a survival advantage in changing environments.
Which of the following is NOT an advantage of vegetative propagation?
- Plants raised can bear flowers and fruits earlier.
- It allows propagation of plants that have lost the capacity to produce seeds.
- It introduces significant genetic variation in offspring. (correct)
- All plants produced are genetically similar to the parent plant.
Why: Vegetative propagation produces genetically identical offspring, not varied ones.
Why is the sexual mode of reproduction considered advantageous over the asexual mode in terms of generating variation?
- It ensures exact copies of DNA are made.
- It combines variations from two different individuals. (correct)
- It is a much faster process than asexual reproduction.
- It prevents any mutations from occurring.
Why: Sexual reproduction combines genetic material from two parents, increasing variation.
What is the primary function of the seminal vesicles and the prostate gland in the male reproductive system?
- To produce sperm.
- To transport urine.
- To add secretions that make sperm transport easier and provide nutrition. (correct)
- To regulate body temperature.
Why: These glands provide fluid and nutrients for sperm.
Match the organism with its mode of asexual reproduction.
Why: Each organism uses a distinct asexual reproductive strategy.
Match the reproductive part/structure with its function.
Why: Each part plays a specific role in reproduction.
Match the contraceptive method with its mechanism.
Why: Different contraceptives work through distinct mechanisms.
Match the organism with the type of fission it undergoes.
Why: Fission patterns vary among unicellular organisms.
The period during adolescence when reproductive tissues begin to mature is called _______.
Why: Puberty marks the onset of sexual maturity.
The process of cell division that results in half the number of chromosomes in germ-cells is called _______.
Why: Meiosis reduces chromosome number by half for gamete formation.
The transfer of pollen grains from the anther to the stigma of a flower is known as _______.
Why: Pollination is the transfer of pollen, a prerequisite for fertilization in plants.
Arrange the following events in the correct sequence for sexual reproduction in flowering plants: 1. Fertilisation, 2. Germination, 3. Pollination, 4. Formation of zygote, 5. Development of embryo.
Why: The correct sequence is Pollination, Fertilisation, Zygote formation, Embryo development, Germination.
Arrange the following parts of the human female reproductive system in the order an egg travels after being released from the ovary: 1. Uterus, 2. Vagina, 3. Fallopian tube, 4. Cervix.
Why: Egg travels from fallopian tube to uterus, then through cervix and vagina.
Identify the structure labeled 'P' in the provided diagram of a germinating seed.
- Radicle
- Cotyledon
- Plumule (correct)
- Seed coat
Why: P represents the plumule, which forms the future shoot.
What does the arrow 'Q' indicate in the diagram of binary fission in Amoeba?
- Cytoplasmic division (correct)
- Nuclear division
- Bud formation
- Spore release
Why: Arrow Q shows the cell membrane pinching, indicating cytoplasmic division.

Hard (10)

Assertion (A): Variation is beneficial for the survival of species over time. Reason (R): All individuals in a population are equally protected by variations.
Why: Variation benefits the species by allowing some individuals to survive, not all.
Assertion (A): Regeneration is not the same as reproduction. Reason (R): Most organisms would not normally depend on being cut up to be able to reproduce.
Why: Regeneration is distinct from reproduction because it's not a normal reproductive strategy.
Assertion (A): The male germ-cell is motile and the female germ-cell contains stored food. Reason (R): This specialisation helps in efficient fusion and provides initial nourishment to the zygote.
Why: Gamete specialization aids fertilization and early embryo survival.
A farmer wants to grow banana plants that are genetically identical to a high-yielding parent plant and also bear fruits earlier than those grown from seeds. Which of the following methods would be most suitable?
- Growing from seeds produced by sexual reproduction.
- Using vegetative propagation methods like layering or tissue culture. (correct)
- Allowing cross-pollination between different banana varieties.
- Encouraging spore formation from the parent plant.
Why: Vegetative propagation ensures genetic similarity and early fruiting.
A couple is concerned about preventing both pregnancy and sexually transmitted infections (STIs). Which contraceptive method would be most effective for their needs?
- Oral contraceptive pills
- Copper-T
- Condoms (correct)
- Surgical methods (vasectomy/tubectomy)
Why: Condoms offer protection against both pregnancy and STIs.
A scientist observes a single-celled organism that has a whip-like structure and divides in a definite orientation. Based on this observation, which organism is it most likely to be?
- Amoeba
- Plasmodium
- Yeast
- Leishmania (correct)
Why: Leishmania exhibits binary fission in a definite orientation due to its flagellum.
Which of the following statements about the process shown in the diagram is/are correct?
- It represents sexual reproduction.
- The new individuals are genetically identical to the parent. (correct)
- It is a characteristic of complex multicellular organisms.
- It involves the fusion of gametes.
Why: Budding is asexual, producing genetically identical offspring.
Observe the diagram showing spore formation in Rhizopus. What is the significance of the thick walls covering the spores?
- They help in photosynthesis.
- They protect the spores from unfavorable conditions. (correct)
- They aid in the dispersal of spores by wind.
- They provide nutrition for the growing hyphae.
Why: Thick walls protect spores, enabling survival in harsh conditions.
Which of the following statements are true regarding sexual reproduction in human beings? Select all that apply.
- Fertilisation usually occurs in the uterus.
- The embryo gets nourishment from the mother's blood via the placenta. (correct)
- Sperm formation requires a temperature higher than normal body temperature.
- The development of the child inside the mother's body takes approximately nine months. (correct)
Why: Fertilization is in the fallopian tube; placenta nourishes embryo; sperm needs lower temperature; gestation is nine months.
Which of the following are benefits of practicing vegetative propagation for certain plants? Select all that apply.
- It helps in producing plants with genetic variations.
- Plants raised can bear flowers and fruits earlier. (correct)
- It enables propagation of plants that have lost the capacity to produce seeds. (correct)
- It makes plants more resistant to all types of diseases.
Why: Vegetative propagation allows earlier fruiting and propagation of seedless plants.