An observation is something you saw happen whereas an inference is something you think will happen. You can guess that the water will fall through a static filled comb, but you observed the water moved away from the comb instead. (I saw this happen and I thought it was so cool)
The population size should decrease at higher trophic levels. The reason is there isn't enough prey to feed the predators as the trophic levels increase. For example, the biggest impact in the ocean would be if you lost all the small fish in an ocean because the predators would be left with less food. It's not exactly correlating, but if you think a little about the statistics it makes sense.
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Answer:
In animals, the process of respiration is aerobic respiration, exchange of gases takes place ( carbon dioxide leaving the cell, oxygen entering)
Single cellular organisms can exchange gases directly across their cell membrane through the process o diffusion.
Large animals cannot maintain gas exchange by diffusion across their outer surface. A respiratory surface is covered with thin, moist epithelial cells that allow oxygen and carbon dioxide to exchange. Those gases can only cross cell membranes when they are dissolved in water or an aqueous solution, thus respiratory surfaces must be moist.
Explanation: