The term "life span" refers to the total duration of an individual's life, from birth until death. It is a measure of how long an organism lives and can vary greatly between species and individuals within a species due to various factors such as genetics, environment, health, and lifestyle choices. The average lifespan for humans varies widely depending on geographic location, socioeconomic status, and other demographic factors. In general, however, the human life span has been increasing over time due to advances in medicine, technology, and overall quality of life.