Life span refers to the duration of time that an organism is expected to live. It varies significantly among different species, influenced by factors such as genetics, environment, and lifestyle. For example, the average life span of a house cat is around 15 years, while tortoises can live for over 100 years. In humans, life span has increased over the past century due to advancements in medicine, nutrition, and public health. The average life expectancy for people in many developed countries is now around 80 years. However, individual life spans can differ based on health, habits, and access to healthcare.