Which of the following is a nitrogenous base?
A) ribose
B) guanine
C) enzyme
D) cysteine

Radiometric dating is used to tell the absolute age of materials by studying the decay rate of radioactive isotopes. the decay rates of isotopes are constant and are expressed as .

Body temperature is tightly regulated in mammals for example when external temperatures drop too much the body of a mammal responds by in order to its core temperature?

4. if a cell is placed inside a solution that has a higher concentration of solute than on the inside of the cell, what can be said about the movement of water? a. water will move out of the cell, causing it to shrivel. b. water will move in and out of the cell at the same rate. c. water will move out of the cell, causing it to swell. d. water will move into the cell, causing it to swell.