Definition - What does Life Span mean?
Life span or life expectancy describes the maximum or average amount of time that an organism, species, group, material, or substance may live for or last without breaking down. It is measured using the time of birth or the time of appearance (when a material may physically develop) or construction (when dealing with man-made productions), as well as expected life span taken from other samples of the same kind.
Safeopedia explains Life Span
Life span is influenced by many factors such as health or diet, medical care and hazards within the environment of an organism. Environmental factors of all kinds have a large influence on the average life span of humans and animals as well as plant life. Modern medical care has caused dramatic increase in life expectancy among humans over the past century.