Answer:
d.when one organism eats another organism, energy is moved
Step-by-step explanation:
Organisms in an ecosystem require energy for their life functions. This energy is derived when they feed on one another in a feeding pattern called FOOD CHAIN. A food chain always starts with a PRODUCER, which is an autotrophic organism that makes its own food via sunlight energy. Hence, the energy flow starts with these producers. Organisms called PRIMARY CONSUMERS feed on the producers and the energy moves to them.
Another set of organisms called SECONDARY CONSUMERS feed on the primary consumers and the energy moves again. Note that, as the energy moves from one organism to another in the food chain, only about 10% of the total eis available to the next organism as about 90% is lost in form of heat when the organism undergoes metabolic activities. Hence, as the energy flow progresses, the available energy decreases.