Phytoplankton are microscopic plants that are the base of the food chain in most of the ocean.
(Phytoplankton; are; microscopic plants that are the base of the food chain in most of the ocean) (microscopic plants; are; the base of the food chain in most of the ocean)
Phytoplankton microscopic plants
are are
microscopic plants that are the base of the food chain in most of the ocean
the base of the food chain in most of the ocean