Characteristics. 1  Closed pockets of tissue that can be filled with fluid or pus. 2  Can appear anywhere on the skin. 3  Smooth to the touch; feels like a pea underneath the surface. 4  Slow growing and generally is painless and benign. 5  Only needs attention if it becomes infected or inflamed.
It has long been recognized and documented that insects are the most diverse group of organisms, meaning that the numbers of species of insects are more than any other group. In the world, some 900 thousand different kinds of living insects are known. This representation approximates 80 percent of the world's species. The true figure of living species of insects can only be estimated from present and past studies.
Invertebrates, animals without a notochord or backbone, comprise the largest group of organisms in the world, forming over a million species. Marine invertebrates alone comprise thousands of species, and are a hugely diverse group of animals, from sessile sponges to spiny sea urchins.