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.
Animals in the class Amphibia spend part of their lives under water and part on land. Frogs, toads, and salamanders are amphibians. Many of these species must keep their skin moist by periodically returning to wet areas. All of them must return to water in order to reproduce because their eggs would dry out otherwise.