All plankton are microscopic (too small to see without a microscope).
algae
zooplankton
prokaryotes
the ocean
Millions of cells
Hundreds of cells
Thousands of cells
A few dozen cells
plants
aquatic (water-living)
microscopic
drifting or wandering
phytoplankton
eukaryotes
To scare away predators
To attract a mate
To see in the dark
Just for fun
it kills large predators like sharks.
it makes the water more acidic.
it makes the water saltier.
Zooplankton are tiny animals.