Question

how is carbon dioxide used by plants

Answer 1

whenever humans exhale carbon dioxide, plants take it in and use it to make a mixture of sunlight and water to create nutrients for itself. Once it creates the nutrients it releases oxygen which us humans use to breathe. This operation is called photosynthesis.

Answer 2

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.