Green plants synthesise food by the process of?

Photosynthetic pigments like as chlorophyll a, chlorophyll b, carotene, and xanthophyll mediate the process of photosynthesis, which occurs largely in chloroplasts. In green plants and a few other autotrophic species, photosynthesis uses carbon dioxide, water, and sunlight to survive. 

As a by-product of photosynthesis, oxygen is produced. Several prokaryotes including cyanobacteria, purple bacteria, and green sulphur bacteria.