Cells continually generate carbon dioxide and must get rid of it. the mechanism whereby carbon dioxide moves out of the cell is called

Cellular respiration

c. heat from the poles back down towards the equator.

the answer is true when observing or determining population size, a direct observation is use, in which each organism is counted in a population or in an area. one benefit of this measure is that you get the exact population count but it will take a long time to  determine  the  size  of a  population.