What do repeated trails in an experiment allow scientists to do?

Which of the following is a possible reason for sleep? a) growth b)digestive c)speed d)intelligence

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

What are characteristics of minerals? select 3 choices