Which snail population has the larger average shell thickness, the population from 1871, or the population from the 1980s?

the population from the 1980s had larger average shell thickness.

Explanation:

The snail population from the 1980s had larger average shell thickness.

The reason is explained as follows.

In the 19 the century , a species of crab called green crab moved to North America . They moved to Cape Cod region . They were predators and used to feed on snails . So a new species of snail evolved there which had thicker cover of shell to protect them from their predators. This was a burning example of process of evolution in modern times. The present generation of snails there now had thicker shell than their ancestors.

b. lithosphere, asthenosphere, mesosphere   is the answer most likely

the electromagnetic energy from the sun arrives in the form of visible and invisible light.