this answer is B. full landfill and another answer is Agricultural runoff (apex)
There are thought to be between 60,000 and 200,000 protist species, and many have yet to be identified. Protists live in almost any environment that contains liquid water. Many protists, such as the algae, are photosynthetic and are vital primary producers in ecosystems.
Other types of enzymes can put atoms and molecules together. Breaking molecules apart and putting molecules together is what enzymes do, and there is a specific enzyme for each chemical reaction needed to make the cell work properly.
https://science.howstuffworks.com/life/cellular-microscopic/cell2.htm
The top layer carry out photosynthesis
