Describe one way the release of sweat allows the skin to function as part of the human excretory system.

There are sweat glands in the skin that excrete said sweat.

the answer would be..

b. sucking

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.