Define the life span. Give the lifespan of an elephant.

Hint: Lifespan related to a fixed duration or period of time. It varies from organism to organism and it usually does not correlate with the size or level of complexity of an organism. But it may be affected by physical health.

Complete answer:
Life span can be defined as the time period or duration starting from birth and ending at the natural death of an organism. It provides us with a rough idea of how long an organism is going to survive.

The life span of elephants ranges from 60 years to 90 years.

Additional Information:
- Life span is not an exact value, it is just an average approximation, therefore many a time exceptions are found. We often hear news like the oldest human being is 126 years old or something like that. In these cases, the particular organism usually exceeds the average life span and this is known as the maximum life span of that organism.
- Life span depends on certain factors that are related to the health of an organism. A diseased organism usually has a lower life span compared to a healthier organism.
Factors affecting the lifespan of an organism include:
> Rate of metabolism: A healthy and fast metabolic rate usually increases life span.
> Habitat: The habitat and changes in habitat also influence the life span.
> Food Quality: Nutritious food helps to increase life span if consumed in a controlled amount.

Note: We should remember that this concept of life span does not apply to unicellular organisms like amoeba, prokaryotes, etc. This is because the phenomenon of death does not take place in them, these organisms just grow in size, and when the nucleo-cytoplasmic ratio exceeds a certain amount they just divide and give rise to a new organism. The genetic information is also passed on to the next generation. These organisms are considered immortal.