After scent molecules are dissolved in the mucous inside the nose, they are accepted by the scenting cells and the impulses occur that send messages to the brain. One theory is that the molecules for each scent are different in shape. Another theory is that smell is a matter of each molecule of scent having a given radio frequency level. There is another little nerve, just under the nose, that can sense different radio frequencies. This theory is not too popular and is not proven.
Deodorants kill the bacteria.
Anti perspirants try to reduce the amount of sweat your body scent. This is because the water coming downward meets and obstructs the upward current of rafts. Thus, you always smell worse as you first leave a shower because you have held and accumulated the rafts for a few minutes. Animals have the apocrine sweat glands over the entire body, but humans only has eccrine sweat glands all over the body. More odor, therefore, is produced on the animals body than on the humans.