The answer is D, for when one tropic level is eaten by the tropic level above it, the tropic level is supporting the higher one. I. E. Rabbits are supported by the grass because rabbits eat the grass. Also, the grass population would be larger than rabbits, the rabbits larger than snakes, so on and so forth, so B is ruled out. B states that each population is larger than the one BEFORE it, but there is no way there would be more rabbits than grass. Also, there are both herbivores and carnivores in the food chain, so A and C are out. The best answer is D.
Water, air, food. and heat.
The answer is d., nervous tissue that promotes movement in the muscle tissue, triggers the brain on what muscle tissue needs to move, as in walking or lifting weights...
Structure and function-there are only TWO types of cells-prokaryotic and eukaryotic
