Biology is the section of science that deals with organisms. Biology is a standard subject in primary courses for school students around the world. It studies the structure, growth, origin, evolution and classification of all organisms. There are a few theories, based on which the basic principles of modern biology are formed.

Biology can be primarily classified into three divisions, based on the subject of the study: Botany, or the study of plants; Zoology or the study of animals; and Microbiology, which deals with the study of microorganisms. However, there are several branches of biology, and some of them are biochemistry, cellular biology, molecular biology, ecology and many more. There have been continuous developments in most branches of biology, based on the main theories of cell theory, evolution, genetics, energy and homeostasis. Researches in biology have often been directly helpful to the cause of medical science, another closely related section of science.