What is the nature of the p-o bond in phosphorus pentoxide (p2o5)?
a.) nonpolar covalent
b.) moderately polar covalent
c.) highly polar covalent
d.) ionic
e.) polar ionic

C.) highly polar covalent

Explanation:

The electronegativity value of P and O are 2.1 and 3.5 respectively, with O atom being more electronegative than P atom. The electronegativity difference in the P-O bond is 1.4.  

In polar covalent bonds the electronegativity difference between two atoms is between 0.5 and 2.0. In nonpolar bonds the electronegativity difference between the two atoms is less than 0.5. And in ionic bonds the electronegativity difference between the two atoms is greater than 2.0.  

geosphere and hydrosphere.

this is because the geosphere has to do with geological events, while the hydrosphere controls all water on earth.