📘 How Do Organisms Reproduce? – MCQs (Class 10 Science)

🔹 Part 3: Questions 51–75

Q51. In humans, the number of chromosomes in zygote is:

A) 23
B) 46
C) 92
D) 44

Correct Answer: B) 46

Explanation:

• A) 23 → Haploid gametes.
• ✅ B) Zygote has 46 (23 from sperm + 23 from ovum).
• C) 92 → Never in humans.
• D) 44 → Autosomes only, ignores sex chromosomes.

Q52. Which structure in flowers develops into seeds?

A) Ovary
B) Ovule
C) Stigma
D) Petals

Correct Answer: B) Ovule

Explanation:

• A) Ovary → Becomes fruit.
• ✅ B) Ovule → Fertilized ovule develops into seed.
• C) Stigma → Receives pollen.
• D) Petals → Attract insects.

Q53. Which of the following diseases is NOT sexually transmitted?

A) Gonorrhea
B) AIDS
C) Syphilis
D) Tuberculosis

Correct Answer: D) Tuberculosis

Explanation:

• A, B, C → STDs.
• ✅ D) TB → Spread by air, not sexual contact.

Q54. Which part of human sperm carries genetic material?

A) Tail
B) Middle piece
C) Head
D) Acrosome

Correct Answer: C) Head

Explanation:

• A) Tail → Movement.
• B) Middle piece → Mitochondria for energy.
• ✅ C) Head → Contains nucleus with DNA.
• D) Acrosome → Helps penetrate ovum.

Q55. Which of the following is NOT a function of placenta?

A) Provides oxygen to embryo
B) Removes waste from embryo
C) Produces hormones
D) Produces gametes

Correct Answer: D) Produces gametes

Explanation:

• A, B, C → True functions of placenta.
• ✅ D) Gametes are produced by gonads, not placenta.

Q56. The unit of inheritance passed from parents to offspring is called:

A) DNA
B) Gene
C) Chromosome
D) Protein

Correct Answer: B) Gene

Explanation:

• A) DNA → Made of many genes.
• ✅ B) Gene → Specific unit of heredity.
• C) Chromosome → Structure carrying genes.
• D) Protein → Not hereditary unit.

Q57. Which of the following is NOT an asexual reproduction method in plants?

A) Budding
B) Cutting
C) Grafting
D) Pollination

Correct Answer: D) Pollination

Explanation:

• A, B, C → Asexual propagation methods.
• ✅ D) Pollination → Sexual reproduction process.

Q58. Which statement is correct for fertilization in humans?

A) Takes place in uterus
B) Takes place in fallopian tube
C) Takes place in ovary
D) Takes place in vagina

Correct Answer: B) Takes place in fallopian tube

Explanation:

• A) Uterus → Embryo development.
• ✅ B) Fertilization happens in fallopian tube.
• C) Ovary → Produces eggs, no fertilization.
• D) Vagina → Birth canal.

Q59. Which method is common for both plants and animals?

A) Fission
B) Budding
C) Fragmentation
D) Sexual reproduction

Correct Answer: D) Sexual reproduction

Explanation:

• A, B, C → Limited to some organisms only.
• ✅ D) Sexual reproduction → Universal in both plants and animals.

Q60. Which of the following is a temporary method of contraception?

A) Vasectomy
B) Tubectomy
C) Condom
D) Surgical removal of uterus

Correct Answer: C) Condom

Explanation:

• A, B, D → Permanent or long-term methods.
• ✅ C) Condom → Temporary barrier method.

Q61. The transfer of pollen grains from anther to stigma of same flower is called:

A) Cross-pollination
B) Self-pollination
C) Fertilization
D) Regeneration

Correct Answer: B) Self-pollination

Explanation:

• A) Cross-pollination → Between different flowers.
• ✅ B) Self-pollination → Same flower.
• C) Fertilization → Fusion of gametes.
• D) Regeneration → Asexual reproduction.

Q62. Which part of human male reproductive system provides fluid medium for sperm transport?

A) Prostate gland and seminal vesicle
B) Testes
C) Scrotum
D) Vas deferens

Correct Answer: A) Prostate gland and seminal vesicle

Explanation:

• ✅ A) Secrete fluid → Protects and nourishes sperm.
• B) Testes → Produce sperm.
• C) Scrotum → Temperature regulation.
• D) Vas deferens → Duct, no secretion.

Q63. Which of the following prevents implantation of embryo?

A) Copper-T
B) Condom
C) Oral pills
D) Vasectomy

Correct Answer: A) Copper-T

Explanation:

• ✅ A) Copper-T → Intrauterine device, prevents implantation.
• B) Condom → Prevents sperm entry.
• C) Pills → Prevent ovulation.
• D) Vasectomy → Blocks sperm ducts.

Q64. The period of pregnancy in humans is about:

A) 9 weeks
B) 9 months
C) 6 months
D) 12 months

Correct Answer: B) 9 months

Explanation:

• ✅ B) Gestation period in humans ≈ 9 months (about 280 days).
• A, C, D → Incorrect values.

Q65. Which of the following prevents fertilization?

A) Copper-T
B) Oral contraceptive pills
C) Condom
D) All of the above

Correct Answer: D) All of the above

Explanation:

• ✅ All methods prevent fertilization by different mechanisms.

Q66. Which type of reproduction ensures variation in organisms?

A) Asexual reproduction
B) Vegetative propagation
C) Sexual reproduction
D) Binary fission

Correct Answer: C) Sexual reproduction

Explanation:

• A, B, D → No variation, produce clones.
• ✅ C) Sexual reproduction → Genetic recombination ensures variation.

Q67. What type of reproduction occurs in yeast?

A) Binary fission
B) Budding
C) Fragmentation
D) Sporulation

Correct Answer: B) Budding

Explanation:

• A) Binary fission → Amoeba.
• ✅ B) Yeast reproduces by budding.
• C) Fragmentation → Spirogyra.
• D) Sporulation → Rhizopus.

Q68. The surgical method of contraception in females is called:

A) Vasectomy
B) Tubectomy
C) Copper-T
D) Condom

Correct Answer: B) Tubectomy

Explanation:

• A) Vasectomy → Males.
• ✅ B) Tubectomy → Fallopian tubes cut/blocked.
• C) Copper-T → Device in uterus.
• D) Condom → Temporary barrier.

Q69. Which type of fertilization takes place in humans?

A) External fertilization
B) Internal fertilization
C) Both internal and external
D) None

Correct Answer: B) Internal fertilization

Explanation:

• ✅ B) Humans → Fertilization inside female body.
• A) External → Fishes, frogs.
• C, D → Wrong.

Q70. Which of the following is a flowering plant that reproduces through vegetative propagation by roots?

A) Bryophyllum
B) Potato
C) Sweet potato
D) Rose

Correct Answer: C) Sweet potato

Explanation:

• A) Bryophyllum → Leaf buds.
• B) Potato → Stem tuber.
• ✅ C) Sweet potato → Roots.
• D) Rose → Stem cutting.

Q71. Which is a temporary contraceptive method?

A) Vasectomy
B) Tubectomy
C) Condom
D) Hysterectomy

Correct Answer: C) Condom

Explanation:

• A, B, D → Permanent methods.
• ✅ C) Condom → Temporary, reversible.

Q72. In vegetative propagation, offspring are genetically:

A) Different from parent
B) Identical to parent
C) Half like mother and father
D) Always sterile

Correct Answer: B) Identical to parent

Explanation:

• A, C, D → Wrong.
• ✅ B) Vegetative propagation → Produces clones.

Q73. Which organ produces sperms in human males?

A) Prostate gland
B) Testes
C) Scrotum
D) Epididymis

Correct Answer: B) Testes

Explanation:

• A) Prostate → Fluid.
• ✅ B) Testes → Spermatogenesis.
• C) Scrotum → Protective sac.
• D) Epididymis → Storage.

Q74. Which contraceptive method provides protection against STDs?

A) Condom
B) Copper-T
C) Oral pills
D) Tubectomy

Correct Answer: A) Condom

Explanation:

• ✅ A) Condoms → Barrier against sperm and infection.
• B, C, D → Prevent pregnancy only, not STDs.

Q75. Which of the following is a viviparous organism?

A) Frog
B) Hen
C) Human
D) Fish

Correct Answer: C) Human

Explanation:

• A) Frog → Oviparous.
• B) Hen → Oviparous.
• ✅ C) Humans → Viviparous, give birth to young ones.
• D) Fish → Mostly oviparous.

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