What happens to air pressure as altitude or
elevation increases? Why?

pressure decreases with increasing altitude

Explanation:

At higher elevations there are fewer air molecules such as oxygen above a given surface than a similar surface at lower levels.

Example : There is less oxygen to breathe at the top of a high mountain than there is at sea level.  

a polymer is a chainlike molecule made up of small molecular units. these small molecular units are called monomers. monomers of polymer can be joined together either naturally or synthetically.  

the answer would be d : p