The Earth is closest to the Sun in:

The following are all types of air masses except:

A pressure gradient is which of the following?

What force causes surface winds to blow across isobars, unlike at upper levels?

When it is March and spring in the Northern Hemisphere, it is __________ and ___________ in the Southern Hemisphere.

The primary force that initially causes air to move horizontally is the:

What type of air mass would be responsible for hot, humid summer weather in the eastern half of the United States?

During dehydration the body would increase production of

The primary follicle develops from the

Testosterone is secreted by the