Question

Planets use carbon dioxide for?

Answer 1

In a process called “photosynthesis,” plants use the energy in sunlight to convert CO2 and water to sugar and oxygen. The plants use the sugar for food; food that we use, too, when we eat plants or animals that have eaten plants and they release the oxygen into the atmosphere.
So it’s PHOTOSYNTHESIS

Answer 2

Plants use CO2 for a process called photosynthesis
it is required to produce the food for the plant

water , CO2 in presence of sunlight and chlorophyll produce C6H12O6
or glucose.