d. the flow of electric charge
Actually it already seems to be matched with the right answer just see the number and what it says below is actually correct.
Answer:
Helps the body make proteins and certain brain-signaling chemicals.
Explanation:
Your body changes L-tryptophan into a brain chemical called serotonin. Serotonin helps control your mood and sleep.
Answer:
B. So that the laws reduce pollution by a significant amount
If you're going to ban something from happening so that you reduce pollution, you would want to consult with a specialist in that area, so you would go to a scientist, who would be able to tell you what to do to lower the pollution by a significant amount by not only telling them what to make stop happening, but what to add or remove in the water.
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Explanation:
The nucleus is inside of a cell and is enclosed with the cell membrane