Ageothermal heat pump can be used to provide drinking water to a city cool a house during the summer generate electricity purify sewage

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

Ascientific idea becomes valid when it is what?

Speed is the ratio of the distance of an object moves to