This is the process by which light energy, water, and carbon dioxide are converted into carbohydrates like starch.
It occurs through a photosynthetic pigment called chlorophyll.
Organisms that undergo photosynthesis are called autotrophs.
Protists
These are organisms belonging to the kingdom Protista.
It includes free-living or colonial eukaryotic unicellular organisms that can be aquatic, terrestrial or marine.
They can be autotrophs(make their own food) like algae, diatoms, or heterotrophs (depend on others for food) like paramecium, amoeba, trichomonas etc or saprotrophs (fungi-like) like slime molds.
Protists include autotrophs that can carry out photosynthesis.
The protists such as algae, diatoms, dinoflagellates and euglena undergo photosynthesis.
They consume almost half of the world's atmospheric carbon dioxide in this process.
They are considered to be the primary producers of their habitat.