* Carbon dioxide (CO2): This is the source of carbon atoms that will be incorporated into the sugar molecule. Plants obtain CO2 from the air through tiny openings called stomata on their leaves.

* Water (H2O): This provides the hydrogen atoms for the sugar molecule and is also a source of electrons needed for the energy reactions. Plants absorb water from the soil through their roots.

* Light energy: This energy is captured by chlorophyll, a green pigment in plant cells. This light energy is converted into chemical energy stored in the bonds of the sugar molecule.

In summary, photosynthesis uses carbon dioxide, water, and light energy to create glucose (sugar) and oxygen as a byproduct.