The carbon molecules are used for respiration in plants.
Step-by-step explanation:
In the photosynthesis process, the solar energy is used to make glucose or carbon molecules by dividing water and carbon di-oxide bond in the presence of bacteria. Later, this glucose is transformed in pyruvate that secretes ATP through the process of respiration of plant cells.
Some of these molecules of carbon are conserved as starch for later use in plants. These are stored in roots, stem and leaves of plants. It also helps in building cellulose of cell walls.