The body obtains vitamin A in two ways. One is by manufacturing it from carotene, a vitamin precursor found in such vegetables as carrots, broccoli, squash, spinach, kale, and sweet potatoes.The other is by absorbing ready-made vitamin A from plant-eating organisms.he body obtains vitamin A in two ways. One is by manufacturing it from carotene, a vitamin precursor found in such vegetables as carrots, broccoli, squash, spinach, kale, and sweet potatoes.
A catalyst is like adding a bit of magic to a chemical reaction. Reactions need a certain amount of energy in order to happen. If they don't have it, oh well, the reaction probably can't happen. A catalyst lowers the amount of energy needed so that a reaction can happen more easily. A catalyst is all about energy.
Collisions and chemical reactions: These collisions may or may not lead to a chemical reaction, so letâs consider, in a general way, what happens during a chemical reaction. To focus our attention, we will consider a specific interaction, namely the reaction of hydrogen and oxygen gases to form water. [2H 2 + O 2 â 2H 2 O].