Class 9 Reproduction: How Life Continues Mock Test (CBSE)

Topics in Reproduction: How Life Continues

• Asexual reproduction
• Vegetative propagation
• Meiosis and variation in sexual reproduction
• Sexual reproduction in flowering plants
• Pollination
• Fertilisation and seed formation
• Sexual reproduction in animals
• Human reproductive systems
• Pregnancy and childbirth
• Reproductive health

Reproduction: How Life Continues practice questions with answers

1. Q1Multiple choice·1 mark
   Budding is a common method of asexual reproduction in:

   1. (a)Amoeba
   2. (b)Yeast
   3. (c)Plasmodium
   4. (d)Spirogyra
   Show answer and step marks

   1. Correct option: (b) Yeast+1

   Answer: (b)
2. Q2Multiple choice·1 mark
   Meiosis results in the formation of cells with:

   1. (a)Double the chromosome number
   2. (b)Half the chromosome number
   3. (c)Same chromosome number
   4. (d)One-fourth the chromosome number
   Show answer and step marks

   1. Correct option: (b) Half the chromosome number+1

   Answer: (b)
3. Q3Assertion and reason·1 mark
   Assertion (A): Vegetative propagation allows the production of genetically uniform offspring identical to the parent plant. Reason (R): Vegetative propagation involves mitotic divisions of somatic cells without the fusion of gametes.

   1. (a)Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
   2. (b)Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
   3. (c)Assertion (A) is true but Reason (R) is false.
   4. (d)Assertion (A) is false but Reason (R) is true.
   Show answer and step marks

   1. Correct option: (a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A). Vegetative propagation uses only mitotic division of somatic cells with no fusion of gametes, so the offspring are genetically identical to the parent.+1

   Answer: (a)
4. Q4Assertion and reason·1 mark
   Assertion (A): Seeds contain the future plant or embryo which develops into a seedling under appropriate conditions. Reason (R): The ovary of a flower develops into a fruit after fertilisation.

   1. (a)Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
   2. (b)Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
   3. (c)Assertion (A) is true but Reason (R) is false.
   4. (d)Assertion (A) is false but Reason (R) is true.
   Show answer and step marks

   1. Correct option: (b) Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).+1

   Answer: (b)
5. Q5Short answer·2 marks
   State the role of the placenta during pregnancy in human females.
   Show answer and step marks

   1. Passes glucose (nutrients) from the mother's blood to the developing embryo.+0.5
   2. Passes oxygen from the mother's blood to the embryo.+0.5
   3. Any one of: removes wastes produced by the embryo, such as carbon dioxide and urea, into the mother's blood (naming any one waste earns the mark); secretes hormones such as progesterone and oestrogen that maintain the pregnancy; or any other valid role of the placenta.+1

   Answer: The placenta passes glucose and oxygen from the mother's blood to the embryo and removes the embryo's wastes, such as carbon dioxide and urea, into the mother's blood; it also secretes hormones that maintain the pregnancy.
6. Q6Long answer·5 marks
   Explain human reproduction with respect to the female reproductive system and embryonic development: (a) Name the primary female reproductive organs and state their two main functions. (b) Describe the structure and role of the placenta in supporting the growth and development of the foetus.
   Show answer and step marks

   1. Primary female reproductive organs: A pair of ovaries located in the abdominal cavity.+1
   2. Function 1 of ovaries: Production of female gametes (ova/eggs).+0.5
   3. Function 2 of ovaries: Secretion of female hormones (oestrogen and progesterone).+0.5
   4. Structure of placenta: A disc-shaped special tissue embedded in the uterine wall, with villi on the embryo's side surrounded by blood spaces on the mother's side, that connects the developing embryo to the uterine wall.+1
   5. Role 1: Provides glucose and oxygen from the mother's blood to the developing foetus for nourishment.+1
   6. Role 2: Facilitates the removal of waste products like carbon dioxide and nitrogenous wastes generated by the foetus into the mother's blood.+1

   Answer: (a) The pair of ovaries; they produce ova (female gametes) and secrete the hormones oestrogen and progesterone. (b) The placenta is a disc-shaped tissue embedded in the uterine wall, with villi on the embryo's side and blood spaces on the mother's side; it passes glucose and oxygen from the mother's blood to the foetus and removes carbon dioxide and other wastes from the foetus into the mother's blood.

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