Matter and energy always flow from the in ecosystems.
A. consumers to the producers
B. heterotrophs to the autotrophs
C. autotrophs to the consumers

When organisms use organic matter for cellular respiration, ALL the goes back into carbon dioxide, water, and minerals, while ALL the energy leaves the ecosystem as heat. So matter cycles, energy flows through ecosystems. So It is C

Explanation: A. The producers generate food for themselves and others; consumers do not produce anything, instead eating producers, other consumers or both.

B. Autotrophs make food for their own use, but they make enough to support other life as well.Heterotrophs cannot make their own food, so they must eat or absorb it.

So C is correct