Why is each level of the energy pyramid smaller than the level directly below it?
A. Because the sizes of each level show that 10% is consumed by organisms at that level.
B. Because 90% of the energy is passed on to the next level to be used by the organisms there.
C. Because about 10% of the energy is converted to heat when organisms become ill and another 10% when they die.
D. Because 10% of the energy at each level moves to the next level and some additional energy is converted to heat.