Which phrase describes air density? A. increases as altitude increases

B. equals mass divided by volume

C. pushes molecules in one direction

D. exerts less pressure as it increases​

c i think

Explanation:

the number of valence electrons for each molecule or ion is shown beneath the structure. remember hydrogen will not have more than two electrons. this hydrogen is part of a covalent bond (sharing two electrons). a double bond here would cause hydrogen to share four electrons with phosphorus.