What do grey pentagons represent?

The Pentagon is the headquarters building of the United States Department of Defense. As a symbol of the U.S. military, the phrase The Pentagon is also often used as a metonym for the Department of Defense and its leadership.

Explanation:

answer; ///i believe the answer is (antioxidant);

for  example, forests have higher evapotranspiration than other ecosystems,  such  as grasslands, because of their deeper roots and greater leaf area. thus forests have a net moistening effect on the atmosphere and become a moisture source for downwind ecosystems.