What substances would a cell inside a multicellular organism likely need to let

Explanation:

Let's think about this from a human perspective (humans are multicellular organisms).

Humans inhale oxygen to use in cellular respiration. Carbon dioxide is the waste product of the process and it is exhaled.

Humans consume proteins and make proteins in protein synthesis. They are used for all sorts of things such as: hormones, repairing tissues, catalysts, providing structure, and more.

So, clearly, the substance that is let out is carbon dioxide. It is exhaled as waste when we breathe, but proteins are used inside the body.

Some negative coping strategies include smoking, drinking alcohol, or using drugs. It might also include over- and undereating as a way to manage stress. Lashing out at others is another negative way stress shows. Finally, many choose to avoid the problem altogether by sleeping too much, watching TV or playing on the computer hour after hour, and withdrawing from family and friends.