Answer :
The bivalve that was a keystone in Iowa, making sure the water stayed clean and filtered, is shellfish.
What are shellfish?
Shellfish is a term used to describe the fishes that have exoskeleton and are used to eat.
The shellfish is divided into two groups:
- Crustaceans: shrimp, prawn, lobster, etc
- Molluscan/ bivalves: oysters, clams, mussels, etc.
So, the molluscan are believed to keep the water bodies clean
Thus, the keystone species is shellfish.
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