Q1. [4]
The modes by which various organisms reproduce depend on the body design of the organisms. In asexual reproduction, a single individual parent produces offsprings without the involvement of gametes. This method is a common means of increasing the offsprings rapidly under favourable conditions. Asexual reproduction occurs mostly in unicellular organisms, some plants and certain simple multicellular animals.
Read the passage and answer the following questions:
- (a) State the name of the organism in which binary fission takes place in a definite orientation. Also name the disease caused by this organism. [1]
- (b) List any two advantages of producing plants through vegetative propagation. [1]
- (c) Internal choice: [2]
Previously asked in CBSE board exam
2022 31/3/1 Q15
Generated by claude-sonnet-4-6 · 2026-06-15 06:44 · grounding stimulus
Model Answer
(a) Leishmania undergoes binary fission in a definite orientation (along its length). It causes kala-azar (leishmaniasis).
(b) Two advantages of vegetative propagation:
- Plants produced are genetically identical to the parent (desirable traits are preserved).
- Plants bear fruits/flowers earlier than those grown from seeds.
(c) (Standard 2-mark internal choice — answer the chosen option):
Regeneration: Some organisms like Hydra and Planaria can regenerate a whole new individual from cut body parts. Specialised cells proliferate and develop into different cell types and tissues. This is possible because of the high degree of organised cell differentiation in these organisms.
Source: Chapter – How do Organisms Reproduce?, Asexual Reproduction section
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Explanation
- (a): Examiners expect both the organism name (Leishmania) and the disease (kala-azar) for the 1 mark.
- (b): Two distinct advantages needed — genetic fidelity and faster/earlier fruit-bearing are the standard NCERT points.
- (c): Since no specific internal choice was printed, regeneration is used as a representative 2-mark concept. In the actual exam, read your choice carefully and write ~40 words covering definition + example + how it works.
- Answers are grounded in NCERT Class 10 Science, Ch. 8.
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