How Do Organisms Reproduce is an important chapter in Class 10 Science that covers asexual and sexual reproduction, vegetative propagation, pollination, fertilization, human reproductive systems, and reproductive health. Practicing How Do Organisms Reproduce Class 10 MCQs helps students revise key Biology concepts, identify common mistakes, and improve accuracy and confidence before CBSE Board exams.
Students can strengthen their preparation with chapter-wise Class 10 Science MCQs and explore CBSE Board resources for exam-focused revision. For practice across different subjects, the Class 10 MCQs collection and the complete MCQs section provide additional objective questions for school tests and board exam preparation.
Download MCQs for Class 10 Chapter 8 Science PDF
Take your How Do Organisms Reproduce practice with you by downloading the complete Chapter 8 MCQ worksheet.
PDF Document
Fill the form to download this PDF
MCQs for Class 10 Science Chapter 8 with Answers and Explanations
Before attempting the questions, remember that Chapter 8 focuses on the different modes of reproduction in living organisms, human reproductive systems, reproductive health, and the biological importance of reproduction. Understanding concepts is just as important as selecting the correct option.
Q1. DNA copying errors help evolution by:
A. Maintaining exact copies
B. Creating useful variations
C. Causing drastic changes
D. Stopping cytokinesis
Answer: B
Explanation:
DNA replication is highly accurate but not completely error-free. Small copying errors create genetic variations among individuals of a species. These variations may help some organisms survive environmental changes better than others. Over time, beneficial variations are selected through natural selection, improving the chances of survival and evolution of the species while still maintaining the basic body design.
Q2. Yeast multiplies rapidly in a warm sugar solution because:
A. Water causes plasmolysis
B. Sugar provides energy
C. Sugar acts as a hormone
D. Oxygen is essential
Answer: B
Explanation:
Yeast reproduces mainly through budding, which requires energy for growth, DNA replication, and cell division. Sugar serves as an immediate source of carbohydrates, allowing yeast cells to produce ATP efficiently. Distilled water contains no nutrients, so growth remains limited. In a warm sugar solution, favorable conditions support rapid metabolism and multiplication of yeast cells.
Q3. Why does Leishmania divide longitudinally?
A. Rigid cell wall
B. No cytokinesis
C. Presence of flagellum
D. Multiple nuclei
Answer: C
Explanation:
Leishmania possesses a fixed body structure with a flagellum located at one end. This organized arrangement determines the direction in which the cell divides during binary fission. Unlike Amoeba, which lacks a definite shape and can divide in any plane, Leishmania undergoes longitudinal division because its flagellum provides a structural reference point for cytokinesis.
Q4. Grafted mango fruits retain hybrid quality because:
A. Stock changes genes
B. Stock controls fruit traits
C. Scion remains genetically identical
D. Meiosis occurs rapidly
Answer: C
Explanation:
Grafting is a form of vegetative propagation in which the desired shoot (scion) is attached to a rooted plant (stock). Since reproduction occurs through mitotic cell division without fertilization, the genetic makeup of the scion remains unchanged. As a result, fruits produced by the grafted plant retain the same taste, quality, and characteristics as the original hybrid parent.
Q5. Bread mould grows on moist bread because:
A. Needs sunlight
B. Moisture activates spores
C. Darkness forms chlorophyll
D. Dryness releases toxins
Answer: B
Explanation:
Rhizopus spores can remain dormant for long periods due to their protective walls. When they land on moist bread, water activates metabolic processes necessary for germination. The bread also supplies nutrients required for growth. Warm and moist conditions promote the development of hyphae, leading to rapid fungal growth, whereas dry conditions prevent spore germination.
Q6. A DNA mutation before reproduction may cause:
Faster protein synthesis
B. Different proteins and traits
C. DNA rejection
D. No body changes
Answer: B
Explanation:
DNA contains instructions for protein synthesis. A mutation changes the nucleotide sequence, which may alter the amino acid sequence of proteins. Since proteins determine the structure and functions of cells, altered proteins can produce changes in physical traits and biological activities. Therefore, mutations can contribute to variations observed among offspring.
Q7. Correct sequence in flowering plant reproduction:
A. Germination → Fusion → Pollination
B. Pollination → Pollen tube → Fertilization
C. Fertilization → Pollination
D. Triple fusion → Pollination
Answer: B
Explanation:
Sexual reproduction in flowering plants begins with pollination, the transfer of pollen grains to the stigma. The pollen grain germinates and forms a pollen tube that grows toward the ovule. Male gametes travel through this tube and participate in fertilization. This process results in zygote formation and subsequent seed development.
Q8. An emasculated flower still produces fruit. This indicates:
A. Parthenogenesis
B. Nutrient effect of bag
C. Pollen entered naturally
D. Artificial cross-pollination
Answer: D
Explanation:
Emasculation removes stamens and prevents self-pollination. If fruit develops afterward, fertilization must have occurred through pollen obtained from another flower. In controlled experiments, pollen is manually transferred to the stigma before bagging. This confirms successful cross-pollination and demonstrates that fruit formation depends on fertilization rather than the presence of stamens.
Q9. Regeneration is not a normal reproductive method in complex organisms because:
A. Only unicellular organisms regenerate
B. They cannot depend on injury for reproduction
C. Hormones are absent
D. It occurs by budding
Answer: B
Explanation:
Regeneration involves replacing lost body parts through cell division and differentiation. Although organisms like Hydra and Planaria can reproduce through regeneration, complex multicellular organisms possess highly specialized tissues and organs. They cannot reliably form a complete individual from body fragments and therefore do not use accidental injury as a regular reproductive strategy.
Q10. The reference point for Leishmania division is:
A. Vacuole
B. Cilia
C. Flagellum
D. Nucleolus
Answer: C
Explanation:
Leishmania has a flagellum at one end that establishes a definite body orientation. During binary fission, cell division follows this organized structure, resulting in longitudinal splitting. The flagellum therefore acts as an important reference point, ensuring proper distribution of cellular components and coordinated reproduction.
Q11. Why is callus transferred to a second culture medium?
A. For multiple fission
B. For gamete formation
C. To remove mutants
D. To induce differentiation
Answer: D
Explanation:
In tissue culture, a callus is an undifferentiated mass of cells. When transferred to a medium containing specific ratios of plant hormones such as auxins and cytokinins, these cells begin differentiating into roots and shoots. This process ultimately produces complete plantlets. The second medium is therefore essential for organized growth and development rather than simple cell multiplication.
Q12. Why is vegetative propagation preferred in banana and orange?
A. Creates more variation
B. Requires no soil
C. Multiplies seedless elite plants
D. Mixes parental traits
Answer: C
Explanation:
Many commercially important varieties of banana and orange produce few or no viable seeds. Vegetative propagation allows farmers to multiply such plants efficiently. Since it is an asexual method, the offspring remain genetically identical to the parent plant and retain desirable traits such as fruit quality, yield, and disease resistance across generations.
Q13. Plasmodium reproduces asexually by:
A. Multiple fission
B. Budding
C. Fragmentation
D. Cross-fertilization
Answer: A
Explanation:
Plasmodium, the malaria-causing parasite, reproduces through multiple fission during part of its life cycle. The nucleus divides repeatedly inside a host cell before the cytoplasm separates around each nucleus. This process produces numerous daughter cells simultaneously. When released, these offspring infect new cells, allowing rapid multiplication of the parasite within the host.
Q14. How is chromosome number maintained in sexually reproducing organisms?
A. Zygote reduces chromosomes
B. Meiosis forms haploid gametes
C. Mitosis halves chromosomes
D. Sperm destroys chromosomes
Answer: B
Explanation:
Meiosis reduces the chromosome number from diploid (2n) to haploid (n) in gametes. During fertilization, the fusion of male and female gametes restores the diploid chromosome number in the zygote. This mechanism ensures that the species-specific chromosome number remains constant across generations and does not double after every reproductive cycle.
Q15. Pollen tube reaches the ovule due to:
A. Mechanotropism
B. Phototropism
C. Chemotropism
D. Hydrotropism
Answer: C
Explanation:
The pollen tube grows toward the ovule in response to chemical substances released by cells of the ovule and embryo sac. This directional growth is called chemotropism. These chemical signals guide the pollen tube accurately to the egg cell, ensuring successful fertilization and subsequent seed formation in flowering plants.
Q16. The main function of placental villi is to:
A. Mix maternal and fetal blood
B. Increase exchange surface area
C. Prevent fetal movement
D. Digest nutrients
Answer: B
Explanation:
The placenta contains numerous finger-like chorionic villi that greatly increase the surface area available for exchange. Through these structures, oxygen and nutrients pass from the mother to the fetus, while carbon dioxide and wastes move in the opposite direction. Maternal and fetal blood generally do not mix directly during this exchange process.
Q17. Testes perform which two functions?
A. Progesterone production and filtration
B. Sperm production and testosterone secretion
C. Sperm storage and lubrication
D. Estrogen production and cooling
Answer: B
Explanation:
The testes are the primary male reproductive organs. They produce sperm cells through spermatogenesis and also secrete testosterone, the major male sex hormone. Testosterone regulates sperm production and is responsible for the development of male secondary sexual characteristics such as facial hair, deep voice, and increased muscle mass during puberty.
Q18. Why are testes located in the scrotum?
A. To reduce pressure
B. To maintain lower temperature
C. To receive sunlight
D. To remain dry
Answer: B
Explanation:
Sperm production requires a temperature slightly lower than normal body temperature. The scrotum keeps the testes about 2–2.5°C cooler than the abdominal cavity, providing ideal conditions for spermatogenesis. If the temperature rises significantly, sperm production and quality may be affected, reducing male fertility.
Q19. A successful vasectomy results in:
A. No semen production
B. No testosterone secretion
C. Semen without sperm
D. Acidic semen
Answer: C
Explanation:
During vasectomy, the vas deferens is cut or blocked, preventing sperm from reaching the urethra. However, the seminal vesicles and prostate gland continue producing seminal fluid. As a result, ejaculation still occurs normally, but the semen contains no sperm cells, making fertilization impossible while leaving hormone production unaffected.
Q20. If fertilization does not occur, what happens?
A. Endometrium grows continuously
B. Menstruation occurs
C. Egg returns to ovary
D. Scar tissue forms
Answer: B
Explanation:
When fertilization does not occur, hormone levels decline, especially progesterone. As a result, the thickened uterine lining loses support and begins to break down. The unfertilized egg, along with blood and endometrial tissue, is shed through the vagina. This process is known as menstruation and marks the beginning of a new menstrual cycle.
Q21. Condoms are effective because they:
A. Prevent pregnancy and STIs
B. Prevent ovulation
C. Work like IUCDs
D. Only stop bacteria
Answer: A
Explanation:
Condoms act as physical barriers that prevent sperm from entering the female reproductive tract. They also reduce the exchange of bodily fluids during sexual intercourse, helping prevent sexually transmitted infections such as HIV, gonorrhea, and syphilis. This dual protection makes condoms one of the most widely recommended contraceptive methods.
Chapter Snapshot
| Topic | What You Learn |
| Reproduction | Importance and purpose of reproduction |
| Asexual Reproduction | Different methods of reproduction without gametes |
| Sexual Reproduction | Reproduction involving male and female gametes |
| Flowering Plants | Pollination and fertilization |
| Human Reproduction | Male and female reproductive systems |
| Reproductive Health | Contraceptive methods and disease prevention |
Why This Chapter Matters for CBSE Exams
Chapter 8 is one of the most important Biology chapters in Class 10 Science. Questions from this chapter frequently appear in school examinations and board papers.
Benefits of Practicing MCQs from This Chapter
- Strengthens conceptual understanding
- Improves speed and accuracy
- Helps identify weak areas quickly
- Supports board exam preparation
- Makes revision more efficient
- Improves confidence before examinations
Many students focus only on theory. However, practicing objective questions helps test whether concepts are actually understood.
