Question

List and describe briefly five external factors that must be present or provided to sustain life

Answer 1

The five main external factors that must be present or provided t sustain life are:
1. Water 
2. Oxygen
3. Food
4. Atmospheric temperature 
5. Atmospheric pressure
The human body needs water, food and oxygen in order the body functions to work properly.
Not every temperature is temperature at which the human can live. For example: we can not stay alive long period of time at temperature of 60 degrees Celsius.