Answer:
The answer is A.
Explanation:
It can be regulated with negative feedback loops.
A lit candle needs to draw oxygen from the air in order to continue burning. If you limit the amount of air available, the candle's flame eventually goes out once it uses up all the oxygen. Lit candles in smaller jar stop burning first because the oxygen trapped in the jar are fewer than the ones in bigger jars.
The activity of some enzymes requires vitamins. This is because vitamin derivatives contribute to the biochemical mechanisms of these enzymes. These vitamin derivatives belong to a class of molecules known as cofactors, which are organic molecules (called coenzymes) or metallic ions, that assist in the catalytic activity of an enzyme.
It was the trip that Charles Darwin went on in attempt to find the answer of how animals got on earth in the first place and how they changed over time. This later on helped him discover evolution and natural selection. The most significant find on this voyage was that he found that different types of finches evolved to the food around them. Smaller beaks meant the finch ate more small nutrients but larger beaks meant the finch ate more harder prey such as fish and worms.
I believe the answer you are looking for is they are all body systems found in the human body, or organ systems.