Use the drop-down menus to determine which structures of the exocrine system are described below. Secrete mucus that protect organs secretes enzymes that aid in digestion

secrete tears

keep the skin hydrated and soft.

your answer should be c) enjoy!

oxygen = 21% of the atmosphere

nitrogen = 78%

carbon dioxide = 0.1%

argon =0.934%

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.