Related Clues:

• Protozoan
• Stonewort, e.g.
• Marine ___
• Chlorophyta bit
• Microscopic creature
• Algae eater
• Foot of a food chain
• Single-celled organism
• Pond denizen
• Slide presentation?
• Pool problem
• Low life?
• Tiny creature
• Pseudopod possessor
• Microscopic organism