1. Sunlight: Plants need sunlight as their energy source to power the process.

2. Carbon Dioxide (CO2): Plants take in CO2 from the air through tiny pores called stomata on their leaves.

3. Water (H2O): Plants absorb water from the soil through their roots.

4. Chlorophyll: This green pigment found in chloroplasts within plant cells absorbs light energy.

Here's a simplified explanation of the process:

* Light-dependent reactions: Chlorophyll captures light energy and uses it to split water molecules, releasing oxygen (O2) as a byproduct. This energy is stored in molecules called ATP and NADPH.

* Light-independent reactions (Calvin cycle): CO2 from the air is combined with the energy stored in ATP and NADPH to produce glucose (a sugar), which is the plant's food.

In summary, photosynthesis is a complex process where plants use sunlight, CO2, and water to create their own food (glucose) and release oxygen as a byproduct.