Afood chain describes a linear path of feeding relationships among organisms along which (blank) moves within an ecosystem

The correct answer is - energy.

The food chain is the linear path of feeding relationship among organisms along which energy moves up in the ecosystem. There's two basic types of organisms, producers and consumers. The producers are the ones that use the natural elements to produce their own food. The consumers get food by eating the producers, and up the hierarchy they eat other consumers. At the top of the food chain are positioned the predators.

answer; (quadrupled)

a and b because with the other three, they simplify to something else.