D is the correct answer :).
The four inner planets have slower orbits, slower spin, no rings, and they are made of rock and metal. The four outer planets have faster orbits and spins, a composition of gases and liquids, numerous moons, and rings. The outer planets are made of hydrogen and helium, so they are called gas giants.
Decomposers break down dead animals and plants. They usually benefit producers by releasing nutrients back in the soil.
Birds, just like humans, have a four-chambered heart.
