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.
A cold blooded animal, or ectotherm, is one that does not have an internal mechanism for regulating its body temperature. Instead, a cold blooded animal relies on solar energy captured by the environment. Reptiles, amphibians and fish are examples of cold blooded animals.