The reaction of an acid with a base, for example, results in the creation of a salt and water. Some, but not all, reactions can be reversed. See nuclear reaction. An action that results directly from or counteracts another action, especially the change in a body's motion as a result of a force applied to it.
Snakes are cold-blooded creatures, just like amphibians. When a certain animal is cold-blooded, it basically means that they are able to adapt their own internal temperature to that of their environment. When a snake is in a cool environment, their body temperature tends to drop rather quickly.
Cold-blooded creatures take on the temperature of their surroundings. They are hot when their environment is hot and cold when their environment is cold. In hot environments, cold-blooded animals can have blood that is much warmer than warm-blooded animals.