Answer:
The correct answer is option A. "directional selection".
Explanation:
Directional selection is a type of natural selection at which traits with extreme characteristics are selected over traits with medium characteristics. In this case, a long-term climatic change resulted in all seeds that are the fountain of food for finch becoming hard. This will result in a directional selection on bill size in the finch population, where large-billed birds will be selected over small and medium-billed birds.
One of the common arguments why the process of transplanting non-human organs which came from animals may be considered as an ethical act is that antigens on the surface of the non-human organs are not significantly rejected in the process. Although its research is still substantial, it is still considered as a matter of ethical issue.
B. Cell wall because animal cell has its non-fixed shape and plant cell has fixed shape.
