Answer:
The corect answer is autotrophs.
Step-by-step explanation:
Autotrophs are organisms that make their own food by using an energy source. Most of the autotrophs use photon energy present in the sunlight to convert simpler substance like CO₂ and H₂O into complex food like C₆H₁₂O₆. This process is used by green plants, algae and called photosynthesis.
Autotrophs are primary producers which is a food source for consumers or heterotrophs who can not make their food. Respiration is the process by which the glucose is oxidized to release stored energy and converts into CO₂ which is again used by autotrophs for the formation of food.