Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): Organisms living in oceans do not face any water-related problems.
Reason (R): Life on Earth originated in water and is not sustainable without water.
 In the light of the above statements, choose the most appropriate answer from the options given below :
1. Both (A) and (R) are true but (R) does not explain (A).
2. (A) is true but (R) is false.
3. (A) is false but (R) is true.
4. Both (A) and (R) are true and (R) explains (A).
Subtopic:  Life History Variations |
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Identify the correct statements:
Statement I: Many plants depend on sunlight to meet their photoperiodic requirement for flowering.
Statement II: Many animals use photoperiod cues for timing their foraging, reproductive and migratory activities.
Statement III: The spectral quality of solar radiation is not important for life.

1. Only Statement I and Statement II
2. Only Statement I and Statement III
3. Only Statement II and Statement III
4. Statement I, Statement II and Statement III
Subtopic:  Life History Variations |
 85%
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Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): Ability to maintain a constant internal environment enhances the overall ‘fitness’ of the species.
Reason (R): A constant internal environment permits all biochemical reactions and physiological functions to proceed with maximal efficiency.
 In the light of the above statements, choose the most appropriate answer from the options given below :
1. (A) is true but (R) is false.
2. (A) is false but (R) is true.
3. Both (A) and (R) are true and (R) explains (A).
4. Both (A) and (R) are true but (R) does not explain (A).
Subtopic:  Life History Variations |
 88%
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If the stressful external conditions are localised, the organism can:
I. migrate temporarily
II. suspend their development till the return of favourable conditions
III. become ‘regulators’ if they are ‘conformers’

1. Only I and II
2. Only I and III
3. Only II and III
4. I, II and III
Subtopic:  Life History Variations |
 75%
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Darwinian fitness is represented by:

1. Low r value 2. High r value
3. High K value 4. Low K value
Subtopic:  Life History Variations |
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As a part of their reproductive strategy, pelagic fishes:

1. Produce a large number of small-sized offspring
2. Produce a small number of small-sized offspring
3. Produce a large number of large-sized offspring
4. Produce a small number of large-sized offspring
Subtopic:  Life History Variations |
 92%
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Which of the following organisms does not breed only once in their life time?

1. Pacific salmon 2. Marsupial mice
3. Birds 4. Bamboo
Subtopic:  Life History Variations |
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Identify the correct statements:
I: Pacific salmon and bamboo breed many times during their lifetimes.
II: Birds and mammals breed many times during their lifetimes and produce a small number of large-sized offspring.
III: Oysters and pelagic fishes produce a large number of small-sized offspring.
 
1. Only I and II 2. Only I and III
3. Only II and III 4. I, II and III
Subtopic:  Life History Variations |
 89%
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