Why do cells need to have a high amount of surface area relative to their volume

The important point is that the surface area to the volume ratio gets smaller as the cell gets larger. Thus, if the cell grows beyond a certain limit, not enough material will be able to cross the membrane fast enough to accommodate the increased cellular volume. That is why cells are so small.

b. the carbon cycle ensures living things have a source of hydrogen

burning fossil fouls really decrease the carbon in the atmosphere so b