| 1. | Ancestral giraffes with longer necks got more food and left more surviving offspring. |
| 2. | Ancestral giraffes stretched their necks to get food. |
| 3. | It was a divine creation. |
| 4. | The giraffe is the mammal where the number of cervical vertebrae is much more than the number of cervical vertebrae in other mammals. |
| Assertion (A): | One-third of all indigenous inhabitants of Sub-Saharan Africa carry the allele of sickle cell trait. |
| Reason (R): | In areas where malaria is common, there is a survival value in carrying only a single sickle-cell allele (sickle cell trait). |
| 1. | Both (A) and (R) are True but the (R) does not correctly explain (A). |
| 2. | (A) is True but (R) is False. |
| 3. | Both (A) and (R) are True and the (R) correctly explains (A). |
| 4. | (A) is False but (R) is True. |
| 1. | low temperature, volcanic storms, atmosphere rich in oxygen |
| 2. | low temperature, volcanic storms, reducing atmosphere |
| 3. | high temperature, volcanic storms, non-reducing atmosphere |
| 4. | high temperature, volcanic storms, reducing atmosphere containing CH4, NH3 etc. |
| Assertion (A): | Almost all fossils are preserved in sedimentary rock. |
| Reason (R): | Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. |
| 1. | (A) is False but (R) is True |
| 2. | (A) is True but (R) is False |
| 3. | Both (A) and (R) are True and (R) is the correct explanation of (A) |
| 4. | Both (A) and (R) are True but (R) is not the correct explanation of (A) |
| (a) | Climatic changes killed them. |
| (b) | Most of them evolved into birds. |
| 1. | Punctuated equilibrium | 2. | Saltation |
| 3. | Allopatric speciation | 4. | Sympatric speciation |
| Assertion (A): | Evolution by natural selection, in a True sense would have started when cellular forms of life with differences in metabolic capability originated on earth. |
| Reason (R): | Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. |
| 1. | (A) is True but (R) is False |
| 2. | Both (A) and (R) are True and (R) is the correct explanation of (A) |
| 3. | Both (A) and (R) are True but (R) is not the correct explanation of (A) |
| 4. | (A) is False but (R) is True |