A marine layer is an air mass which develops over the surface of a large body of water such as the ocean or large lake in the presence of a temperature inversion. ... As it cools, the surface air becomes denser than the warmer air above it, and thus becomes trapped below it.
A) Natural selection
Hope this helps I took bio ;)
It would be all if u can pick that but if not it depends on what animal the he question is talking about