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प्रश्न
Explain any two alternatives by which organisms can overcome stressful external conditions.
उत्तर
The alternatives by which organisms can overcome stressful external conditions are:
(i) Migrate: Some organisms migrate temporarily from an unfavourable habitat to a more favourable habitat and return when the favourable period is over. Example: Migratory birds move from very cold northern regions to warmer places.
(ii) Suspend: Some organisms avoid the unfavourable environment by escaping from it. Example: Polar bears hibernate during winter to escape extreme cold. Some snails and fish undergo aestivation to avoid summer-related problems such as heat and desiccation.
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संबंधित प्रश्न
In certain seasons we sweat profusely while in some other season we shiver. Explain.
State how the constant internal environment is beneficial to organisms.
Distinguish between Ectotherms and Endotherms
List the various abiotic environmental factors.
Answer the following question.
‘‘Organisms may be conformers or regulators.’’ Explain this statement and give one example of each.
The figure given below is a diagrammatic representation of response of organisms to abiotic factors. What do A, B and C represent respectively.
| S. No. | A | B | C |
| a. | Conformer | Regulator | Partial Regulator |
| b. | Regulator | Partial Regulator | Conformer |
| c. | Partial Regulator | Regulator | Conformer |
| d. | Regulator | Conformer | Partial Regulator |
Homeostasis is ______.
Match List - I with List - II.
| List I | List II | ||
| (a) | Allen's Rule | (i) | Kangaroo rat |
| (b) | Physiological adaptation |
(ii) | Desert lizard |
| (c) | Behavioural adaptation |
(iii) | Marine fish at depth |
| (d) | Biochemical adaptation |
(iv) | Polar seal |
Choose the correct answer from the options given below.
Assertion (A): A person goes to high altitude and experiences ‘altitude sickness’ with symptoms like breathing difficulty and heart palpitations.
Reason (R): Due to low atmospheric pressure at high altitudes, the body does not get sufficient oxygen.
In the light of the above statements, choose the correct answer from the options given below.
Define aestivation.
