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. |
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). |
Assertion (A): | Conformers resign themselves to sub-optimal performance if the prevailing environmental conditions are not in their range of tolerance. |
Reason (R): | An overwhelming majority of animals and nearly all plants cannot maintain a constant internal environment. |
1. | Both (A) and (R) are true and (R) explains (A). |
2. | Both (A) and (R) are true but (R) does not explain (A). |
3. | (A) is true but (R) is false. |
4. | (A) is false but (R) is true. |
I. | migrate temporarily |
II. | suspend their development till the return of favourable conditions |
III. | become ‘regulators’ if they are ‘conformers’ |
Statement I: | Bears go into aestivation to avoid summer related problems – heat and dessication. |
Statement II: | Snails and fish go into hibernation during winter. |
I. | Many adaptations have evolved over a long evolutionary time and are genetically fixed. |
II. | Kangaroo rat has a remarkable ability to concentrate its urine. |
III. | In Opuntia, leaves are reduced to spines and the photosynthetic function is taken over by the flattened stems. |
Assertion (A): | Tribes living in high altitudes of Himalayas normally have a higher RBC count [or total haemoglobin] than people living in the plains. |
Reason (R): | In low atmospheric pressure of high altitudes, the hypoxic conditions lead to an increased production of RBCs by bone marrow. |
1. | Both (A) and (R) are true and (R) explains (A). |
2. | (A) is true but (R) is false. |
3. | (A) is false but (R) is true. |
4. | Both (A) and (R) are true but (R) does not explain (A). |
Assertion (A): | Population ecology links ecology to population genetics and evolution. |
Reason (R): | It is at the population level that natural selection operates to evolve the desired traits. |
1. | Both (A) and (R) are True and (R) explains (A). |
2. | Both (A) and (R) are True but (R) does not explain (A). |
3. | (A) is True but (R) is False. |
4. | (A) is False but (R) is True. |
I. | The ecological role of the banyan tree in this community is negligible when compared to that of carrot grass. |
II. | In this community, the percent cover or biomass is a more meaningful measure of the population size. |
Assertion (A): | The number of fish caught per trap is not a good measure of its total population density in the lake. |
Reason (R): | For ecological investigations, it is obligatory to count every individual in a population to estimate population density. |
1. | Both (A) and (R) are True but (R) does not explain (A). |
2. | Both (A) and (R) are False. |
3. | Both (A) and (R) are True and (R) explains (A). |
4. | (A) is True but (R) is False. |
I. | Nt+1 = Nt + [(B+I) – (D+E)] |
II. | B is a measure of Natality and D is a measure of Mortality |
III. | If (B+I) is less than (D+E), the population density will increase |
1. | Only I and II are correct | 2. | Only I and III are correct |
3. | Only II and III are correct | 4. | I, II and III are correct |