1. which of the following is true about chemical energy?
a. chemical energy can be stored more efficiently as glucose than it can be as atp.
b. chemical energy is stored when bonds in atp are broken to form adp.
c. chemical energy is released when bonds in adp are broken to form atp.
d. chemical energy can only be stored as adp.

What is true of chemical energy is that chemical energy can be stored more efficiently as glucose than it can be as ATP. All the other answers in this case don't really apply. The correct answer is therefore A.

When ATP is broken down to ADP we get a release of energy - B and C are therefore wrong. Energy is broken in more ways as only ADP - D is also wrong. Only A stays as the correct answer. 

C) to ensure each new cell has an exact copy of the dna