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