Where does almost all the energy that drives life on the earth originate?
a. in producer plants
b. in the energy flow of the food web
c. in hydrothermal vents under the sea
d. in the sun

I believe the answer would be D, in the sun. Every form of life on Earth depends upon others, and without sunlight, most life on Earth would cease to exist rather quickly.
More specifically, because animals cannot make their own food, they rely on plants to give them the energy needed to survive. Plants feed animals called herbivores, herbivores feed animals known as carnivores and the decomposers feast on the waste left behind to begin the cycle again. This continuous loop is commonly called the food chain. Without sunlight to help plants make food, most life could not exist for very long.