Hormone molecules are produced by endocrine cells and released into the bloodstream. Describe what must happen for hormones to affect target cells.

Ahypothesis that has been tested again and again , with similar results each time may become a law , true or false

When proteins are being produced by a cell, scientist say that the genes are question 2 options: activated turned off replicated deactivated

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