- Although plants do not have nerves, they do use electrical impulses for coordination. These impulses are like the humans, but much slower. The Venus flytrap plant is a good example.
- A single photon of light – the smallest quantity you can get, is enough to stimulate a rod cell.
- Each off your fingers has about 3000 touch receptors. This is as many as the whole of your back and chest.
- You can survive for weeks without food, but only a few days without water
- A healthy man should have about 15% of his weight as body fat. A healthy woman should have about 25 %.