By how much did carbon dioxide levels increase from 1980 to 2000?

How are the testes and ovaries similar? a. both produce sex cells. b. both connect internal reproductive organs to the exterior. c. both transport sex cells from their site of production. d. both store mature sex cells.

Common symptoms of an iron-defiency anemia include muscle weakness shortness of breath and lightheadedness why does iron deficiency causes these symptoms

Which of the following is the earliest era of earth's geologic time scale? cenozoic mesozoic precambrian paleozoic