Secondary consumers use about of the energy from the primary consumers they eat. 75% 50% 10% 5%

The chemical form of energy that is useable by the cell to do work

Vessels draining the myocardium of the heart, open primarily ,into which chamber?

Which of the following must be true for a fossil organism to be useful as an index fossil? a. the fossil organism must be widespread geographically. b. the fossil organism must be abundant. c. the fossil organism must be limited to a short span of geologic time. d. all of the above.