Life-span refers to the maximum length of life that is biologically possible for a member of a given species under ideal conditions, representing the theoretical upper limit of longevity for that species. For humans, the life-span is generally considered to be around 120-125 years, although very few individuals actually reach this age. It is distinct from life expectancy, which is the average number of years a person is expected to live in a specific population at a given time. While life expectancy can be influenced by various environmental and social factors, the life-span is thought to be more determined by biological and genetic factors inherent to the species.