Answer the following question given this paragraph: 

Plant-like protists are essential to the ecosystem. They are the base of the marine food chain, and they produce oxygen through photosynthesis for animals to breathe. They are classified into a number of basic groups ( Table below ).


Q: Plant-like protists produce oxygen through which process?

 Choices:

- respiration

- metamorphosis

- glycolysis

- photosynthesis

A:
photosynthesis
