NCERT Class 12 Biology: Chapter – 1 Reproduction in Organisms Part 2 (For CBSE, ICSE, IAS, NET, NRA 2022)

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Question 14:

There is no natural death in single celled organisms like Amoeba and bacteria because:

a. They cannot reproduce sexually

b. They reproduce by binary fission

c. Parental body is distributed among the offspring

d. They are microscopic

Answer: (c)

Question 15:

There are various types of reproduction. The type of reproduction adopted by an organism depends on:

a. The habitat and morphology of the organism

b. Morphology of the organism

c. Morphology and physiology of the organism

d. The organism՚s habitat, physiology and genetic makeup

Answer: (d)

Question 16:

Identify the incorrect statement.

a. In asexual reproduction, the offspring produced are morphologically and genetically identical to the parent

b. Zoospores are sexual reproductive structures

c. In asexual reproduction, a single parent produces offspring with or without the formation of gametes

d. Conidia are asexual structures in Penicillium

Answer: (b)

Question 17:

Which of the following is a post-fertilisation event in flowering plants?

a. Transfer of pollen grains

b. Embryo development

c. Formation of flower

d. Formation of pollen grains

Answer: (b)

Question 18:

The number of chromosomes in the shoot tip cells of a maize plant is 20. The number of chromosomes in the microspore mother cells of the same plant shall be:

a. 20

b. 10

c. 40

d. 15

Answer: (a)

Very Short Answer Type Questions

Question 1:

Mention two inherent characteristics of Amoeba and yeast that enable them to reproduce asexually.

Answer:

Unicellular organisms like Amoeba and yeast reproduce asexually because

(i) They have relatively simple organisation and uni-parental condition.

(ii) Asexual reproduction helps them to multiply very fast.

Question 2:

Why do we refer to offspring formed by asexual method of reproduction as clones?

Answer:

Clones are genetically and morphologically similar organisms. In the process of asexual reproduction only single parent is involved so no genetic and morphological variation takes place that is why we refer to offspring formed by asexual method of reproduction as clones.

Question 3:

Although potato tuber is an underground part, it is considered as a stem. Give two reasons.

Answer:

Although potato tuber is an underground part, it is considered as a stem because:

1. They have leaf shoots arising from the nodes.

2. The tuber has internodes.

These characters are seen in stems.

Question 4:

Between an annual and a perennial plant, which one has a shorter juvenile phase? Give one reason.

Answer:

Annual plants have shorter juvenile phase compare to perennial plant. Moreover. It also depends on number of flowering seasons in a given year. Some perennial plants produce flower only once in a year. Some others may produce flowers once in 50 years or even 100 years. This is not the situation in annual plants.