All of the following patterns were witnessed by darwin except that species vary a. within very short spans of time. b. around the world. c. locally. d. over time.

When analyzing tree rings, what do scientists assume a thin ring indicates?

What are the doorways into and out of cells, attached to the membrane, and built in the rough er.

Control of the body is accomplished by which of the following body systems? nervous system and circulatory system endocrine and repertory system circulatory and respiratory systems nervous system and endocrine systems