Answer the following question given this paragraph: 

Humans could not live on Earth if it were not for protists. Why? Plant-like protists produce almost one-half of the oxygen on the planet through photosynthesis. Other protists decompose and recycle nutrients that humans need to live. All protists make up a huge part of the food chain.


Q: What produces almost one-half of the earth's oxygen through photosynthesis?


A:
protists