Physics includes biology.
Biology is a natural science concerned with the study of life and living organisms , including their structure , function , growth , evolution , distribution , identification and taxonomy .. natural science. natural science. life. life. evolution. evolution. taxonomy. Taxonomy ( biology ). Modern biology is a vast and eclectic field , composed of many branches and subdisciplines .. branches and subdisciplines. #Branches. However , despite the broad scope of biology , there are certain unifying concepts within it that consolidate it into single , coherent field .. In general , biology recognizes the cell as the basic unit of life , genes as the basic unit of heredity , and evolution as the engine that propels the creation of new species .. life. life. evolution. evolution. cell. cell ( biology ). genes. genes. heredity. heredity. species. species. It is also understood today that all organisms survive by consuming and transforming energy and by regulating their internal environment to maintain a stable and vital condition known as homeostasis .. energy. energy. regulating. homeostasis. homeostasis. homeostasis. environment. environment ( biophysical ). Sub-disciplines of biology are defined by the scale at which organisms are studied , the kinds of organisms studied , and the methods used to study them  : biochemistry examines the rudimentary chemistry of life ; molecular biology studies the complex interactions among biological molecules ; botany studies the biology of plants ; cellular biology examines the basic building-block of all life , the cell ; physiology examines the physical and chemical functions of tissues , organs , and organ systems of an organism ; evolutionary biology examines the processes that produced the diversity of life ; and ecology examines how organisms interact in their environment .. life. life. organism. organism. cell. cell ( biology ). biochemistry. biochemistry. molecular biology. molecular biology. botany. botany. cellular biology. cellular biology. physiology. physiology. tissues. tissue ( biology ). organs. Organ ( anatomy ). evolutionary biology. evolutionary biology. ecology. ecology. environment. environment ( biophysical )