I attached a image above

D is correct

Explanation:

Phytoplankton are microscopic marine algae.

Phytoplankton, also known as microalgae, are similar to terrestrial plants in that they contain chlorophyll and require sunlight in order to live and grow. Most phytoplankton are buoyant and float in the upper part of the ocean, where sunlight penetrates the water.

Zooplankton are a type of heterotrophic plankton that range from microscopic organisms to large species, such as jellyfish. Zooplankton are found within large bodies of water, including oceans and freshwater systems.

a physical change is being made.