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.
Currently, estimates of the total number of species range from about 10 million to a billion, but these estimates are tentative, and may be off by many orders of magnitude. By comparison, there are probably between 10 and 30 million species of animals, the vast majority of them insects. The number of scientifically recognized species of animals is about 1,250,000. There are almost 300,000 recognized species of plants.