Why isn't atomic emission used to measure all the elements instead of atomic absorption?

Atomic absorption refers to the amount of energy that an atom absorbs energy which is always the same amount of energy that it emits, any given element in the atomic or periodic table will absorb a certain amount of radiated energy and let the rest pass trough and can be seen as emission when viewed at a certain angle. Its is easier and just as precise to measure the energy absorbed and maintained by an element.

Most likely a is the answer - because  you generate   38 atp's but also consume an atp.   each atp gives approx. less than 4 kcal so probably a is the closest answer.

The answer is 1.82 j/g°c