An ecosystem is a group of organisms and the habitat in which they live together. All organisms in an ecosystem interact with each other and their environment. Some organisms interact as part of a food chain or food web. A food web is a complicated set of interrelated food chains all found in one ecosystem. Matter and energy are transferred from one organism to another at each step. They go through the producers like plants, which make their own food, consumers like animals, which eat other living things, and decomposers like bacteria, which break down dead organisms and help cycle energy and nutrients back into the environment.

For example, in the hot African Savannah, a herd of antelope gets energy from the grass they eat. A pride of lions chases down and consumes an antelope, gaining energy from the flesh of their prey. One of the lions is very old, and soon dies. Scavengers gain energy as they pick over his dead body. This is just one example of a string of events that is the food chain.

In the food chain described above, what are the producers?

a. the antelope that eat the grass

b. the scavengers that eat the dead lion

c. the grasses the antelope eat

d. the lions that eat the antelope