They have increased need to carbohydrates, protein, water and iron.
Carbohydrates is the primary source for energy and active people apparently need more energy for their daily activities.
Protein helps build muscles, even though they only need a small amount more of protein than normal people, they still require protein for muscle buildings.
Water has to be needed as they may excrete more sweat by active activities in the day time. Water can also help remove waster material from body.
Iron helps the production of hemoglobin, which is in the red blood cells that help transport oxygen. As they exercise more, they need more oxygen supply for respiration, therefore there is a need for iron supply.
Cancer cells reproduce the same way the other cells reproduce. The difference between cancer cells and others is that their reproduction is uncontrollable. They constantly go through the cell cycle and they reproduce. Two ways cell reproductions are meiosis and mitosis. DNA duplicates itself. Cancer is incessantly receiving messages.
I think the correct answer from the choices listed above is option A. The difference between a normal cell and a cancer cell is that a normal cells undergo while cancer cells don't Also, normal cells respond to signals while cancer cells don't.