three, actually. Food, water, air.
Brain, heart, spinal cord, etc.
When you are no longer able to survive or function efficiently without the thing in question.
Oxygen and nutrients
To function efficiently the eye needs bright light. For maximum efficiency the eye needs light to be at a wavelength of 0.555um. The eye can perform efficiently in the dark at a wavelength of 0.510um, but there is a weakness in color.
Living things need to eat in order to survive; they need to consume nutritions and calories to give them energy and the materials the body needs to function.
oxygen.
Pneumonia affects your body by making it hard for you to breathe.I read that it causeshigh fevershortness of breathchest painjoint and muscle painslow body temperatureincreased respiratory system ratelow blood pressurehigh heart ratePneumonia is a condition that normally affects the lungs. When the lungs cannot function properly other body systems do not get the oxygen they need to operate efficiently.
We need energy in order to function (and live).
We all need protein in our body because then our body will function properly.
It helps the brain function properly!
food, water, and oxygen
A live, healthy body to function in.