Fact 1: Zooplankton are tiny animals that feed on phytoplankton.

Fact 2: Many zooplankton are crustaceans.

Given the two facts above, answer the question "Some crustaceans feed on" with the following options: 
- phytoplankton
 - fungi
 - refraction of light
 - heat energy
 - an organism's body
 - carbon
 - algae
 - salt and water.


 

 phytoplankton        