Fossils of Ambulocetus show that it was about 3 meters long. It had hind legs which were more suited for swimming than for walking. It could hear very well under water, and its teeth resembled those of modern cetaceans. Its limb anatomy suggests that it was slow on land and in the water.
Reactants are the molecules that begin cellular respiration, in this case that would be oxygen<span> and </span>glucose<span>. Hope this helps. </span>