All of your body system with together to or a stable internal balance, in your body?

Asquirrel population lives in an area. over many years, a river in that area grows wider and stronger, eventually forming a canyon. the squirrel populations on the two sides of the canyon can no longer mate with each other and ultimately form distinct species. this is an example of

Natural resources are any materials that humans obtain from the earth to meet our wants and needs.

What is the main fuel source for the work of the cell