Although the terms reactant and reagent are often used interchangeably, a reactant is more specifically a substance that is consumed in the course of a chemical reaction. Solvents, although they are involved in the reaction, are usually not referred to as reactants.
Animals that live in water, usually called aquatic animals, include fish, cetaceans, certain types of turtles and other reptiles, and amphibians. There are also a number of semiaquatic animals, such as alligators, hippopotamuses and penguins, that depend on and live in water most of the time. Continue Reading.
Some  amphibians have a rough leathery skin.  Reptiles are generally bigger in size than amphibians.  Reptiles include four groups of animals-lizards and snakes,  turtles and tortoises, crocodilians, and tuatara. Amphibians  include three groups of animals-frogs and toads, salamanders and  caecillians. Different species of reptiles live on land, in water, or both  on land and in water. However, all amphibians are born in water and  spend early part of their lives in water in form of larvae. Through  a process of metamorphosis the larvae of amphibians grow into  adults which are quite different from the larvae.