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