Explain why a model of the atom is crucial to understanding chemistry and in explaining the behavior of matter. use 3 - 4 sentences in your explanation.

The model of the atom is crucial because without it we wouldn't know how the protons, neutrons, and electrons are connected. Essentially, the protons and neutrons are seen with their bonds while electrons are rotating waves of energy that go around the atom. This model helps us differentiate different elements and isotopes based on the number of components and the way they are connected.

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.

I’m not sure what your trying to say here.. can you clarify again?