What is biology?

Hint: Study of living organisms and everything about life is known as biology. It includes everything like their physical structure, chemical reactions that occur, their relationship with the same species as well as with different species, and with the surrounding environment as well.

Complete step by step answer:
Biology is subdivided into different branches for the convenience of study, it's custom to separate the study of plants (botany) from that of animals (zoology), and therefore the study of the structure of organisms (morphology) from that of function (physiology), all living things share in common certain biological phenomena—for example, various means of reproduction, cellular division, and therefore the transmission of genetic material from one organism to another.

Biology is usually approached on the idea of levels that affect fundamental units of life. At the extent of biology, for instance, life is considered a manifestation of chemical and energy transformations that occur among the various chemical constituents that compose an organism.
Cell biology is the study of cells—the fundamental units of structure and performance in living organisms. Cells were first observed within the $1{ 7 }^{ th }$ century when the compound microscope was invented. There are many more branches of biology like immunology, virology, biotechnology, and the list is very long.

Note: The word biology comes from the Greek word bios which means life and logos means to study. Aristotle is called the Father of Biology. The basic foundation of biology is based on five basic principles. The five basic principles are the cell theory, gene theory, evolution, homeostasis, and laws of thermodynamics.