This is a very vague question but i'd say they are modifying their emotional state
if two animals are held in captivity seperate when they finally meet they will more than likely be hostile to each other because they dont know what a friend is lets take a cat for example dont give a cat a friend and now it sees a interesting laser on the floor and chases it well thats adorable and all but you just taught your cat how to be hostile and hunt and it will do that for the rest of its life well now lets say this cat is 2 and an adult female when she comes across another female or another species of animal she will definitely attempt to fight it because its all she knows
The products are NADPH and ATP.
Yes cuz it been in the same area for decade
Due to the linneaus system of classification scientist were able to identify organism name , group via standardized system . They have found similarities in the organism like DNA / RNA ( genetic composition), embryonic development etc . so that they can study a organism completely . With the help of this system of classification scientist were able to give a particular name to a organism which is standardrized in the whole universe. It makes easier to all to identify an organism , otherwise different places have different name for a particular species.