We all know that animals are one of the most important parts of our lives. We depend on them for food, protection, companionship, and much more. Animals make us laugh, make us cry, make us feel better or in some way that we cannot even begin to explain.

Of all animals there are two that are perhaps closest to being our friends and that is insects and mammals. Both of these categories of animals are highly diverse but unlike some plants and even some insects, mammals have evolved a way to survive by means of their own digestive systems, a mouth to feed off of, while insects rely on other methods to procure nutrients. Insects are multicellular, eusocial animals in the bacterial, protozoan, metamorphic, and other living organisms in the Kingdom Animalia. With few exceptions, animals feed off of organic matter, breathe air, can produce milk, move, are able to reproduce sexually, and can survive with just a single pair of arms and one leg.

Mammoths are a good example of a single-celled organism that needs oxygen to survive. The other class of animals is the Protista which include all land animals and all animals that derive their nourishment from water. Not all living things are classified under the kingdom Animalia, but nearly all of the animals that live within the earth’s environment are categorized in this kingdom.