The diversity of life on Earth is a result of mutations or random changes in hereditary material over time. These mutations allow the possibility for organisms to adapt to a changing environment.
Life is everything that happens: When people say, "That's life," they mean all the events and tendencies, the human condition itself. You might hear about "city life" — or "country life" for that matter — meaning the habits and expectations of inhabitants of a particular place.
Meaning of life The meaning of life is the concept of an individual's life, human life, or existence in general having an inherent significance or a philosophical point. There is no consensus on the specifics of such a concept, or whether the concept itself even exists in any objective sense.
Human evolution, the process by which human beings developed on Earth from now-extinct primates. The only extant members of the human tribe, Hominini, belong to the species Homo sapiens. The exact nature of the evolutionary relationships between modern humans and their ancestors remains the subject of debate.
Human sexuality refers to the expression of sexual sensation and related intimacy between human beings. Biologically, it is the means through which a child is conceived and the lineage is passed on to the next generation.
be hav ior (bi hāv′ yər), n. manner of behaving or acting. Psychology observable activity in a human or animal. the aggregate of responses to internal and external stimuli. a stereotyped, species-specific activity, as a courtship dance or startle reflex. Sociology Often, behaviors. a behavior pattern. the action or reaction of any material under given circumstances: the behavior of tin ...