Answer:
People used stone tools to kill animals for food. People made the stone tools by using a blade and carving the stone tool out.
Explanation:
This is more of a science question, but ok. You see blue light because in the color spectrum blue passes most easily through things. Hence why the sky is blue. Its the light from the sun filtered out and only blue passing all the way through the atmosphere.
The largest internal organ in the body is the liver.