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.
Putting an accurate figure on this question is extremely difficult. The most reliable estimate, based on data from 2005, suggests 115.3 million animals are used in experiments annually (although the authors concluded this âis still likely to be an underestimateâ. It will also exclude virtually all invertebrates).