You are presented with the question "Members of a major food source for humans filter what?" and the following answer choices: 
- gills
 - salmon
 - matter
 - water
 - Air
 - energy
 - sodium
 - Energy.

Now knowing that mollusks are a major food source for other organisms, including humans and mollusks filter the water as they look for food, choose the best answer.


 

    water     