Question

A paleontologist identified two distinct species of mollusks in the fossil record of a region. In the layer below a mass extinction that devastated the region, the paleontologist observed that shells of species A was present in small numbers over a widespread area whereas species B was abundant and found in a few restricted areas. Which of the following predictions about the fossil record in the layer above the mass extinction is the MOST likely to be supported by further excavations?

A. Species A survived because of its widespread range including some areas that were not as affected by mass extinction.

B. Species A survived because the low number of individuals meant that there was less competition for resources.

C. Species B survived because it was the more abundant and more individuals survived.

D. Species B survived because the population was concentrated in a few areas and had a higher chance of survival.

Answer 1

A. Species A survived because of its widespread range including some areas that were not as affected by mass extinction.

Species B is localized in restricted areas. So if any destruction occurs, it will lead to mass extinction. Whereas species A even though small in numbers, lives in widespread areas so mass extinction chances leading to disappearance of species is low compared to Species B.

Thank you.