Answer: Coenzymes
Explanation:
Coenzymes are the small organic molecules that are often derived from the vitamins. It can be tightly or loosely bond to the enzymes.
Tighly bond ones are the prothestic groups and loosely bond ones are coenzymes like the products and substrate which binds to the enzyme and get released from it.
This component is very important for any reaction to take place. It bonds to the enzymes and helps in product formation.
Sink to the bottom because it is more dense than the water.
Well, Euglena is in phylum Euglenophyta, and Paramecium is in phylum Ciliophora. You can verify that with a quick Google search.
<span>Does that sort of narrow it down? :)</span>
