Answer:
C. All plankton are closely related to plants.
Explanation:
Plankton are organisms found in water that exist in a drifting state. They are too small or weak to swim on their own, so they let the current or tide carry them. They are usually microscopic but include larger species as well, such as some crustaceans and jellyfish.
Phytoplankton are autothrophic plankton. This means that they produce their own food. They are primary producers and closely related to plants.
Zooplankton are heterotrophic plankton, which means that they feed on other organisms. They are animals and aren't closely related to plants.
Nekton are organisms found in water that swim actively.
Based on this information, we can conclude that statement C is the only incorrect statement.
