The correct answer of the given question above would be the third option: THE EVOLUTION OF POPULATIONS OVER TIME. What is represented by the base of a phylogenic tree is the evolution of populations over time. It is also known as the evolutionary tree. This tree shows the evolutionary relationships among species.
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.
The answer is near the equator. Hope that helps!