Answer:
1. photosynthesis
2. Carbon dioxide
3. oxygen
Explanation:
Autotrophic beings are organisms capable of producing their own food (organic substances) from inorganic substances taken from the environment. The term autótrofo is of Greek origin where autos means "the own", "alone" and trophos, that feeds. The synthesis of nutrients by autotrophs occurs through photosynthesis.
When the plant is performing photosynthesis, the various carbon atoms that are part of CO2 start to be used in the formation of the organic molecular group. The rest of the molecules end up being degraded by the plant itself during the respiration of the cells. In summary, CO2 and water in the presence of light energy are the reagents of photosynthesis.
The oxygen released by photosynthesis carried out by eukaryotes and cyanobacteria comes from water, not carbon dioxide, as was previously thought. Oxygen and glucose are the products of photosynthesis.