In which group of organisms the cell walls form two thin overlapping shells which fit together?

Explanation

Dinoflagellates:Dinoflagellates are a group of protists, specifically algae. They are unicellular organisms.The cell walls of dinoflagellates are made of cellulose plates, which can form two thin overlapping shells. These plates fit together, creating a protective armor-like structure around the cell. Slime Moulds:Slime molds are not known for having cell walls with two thin overlapping shells that fit together.Slime molds are unique organisms that can exist as both single-celled amoeboid forms and multicellular plasmodial forms, but their cell walls do not exhibit the specific structure mentioned. Chrysophytes:Chrysophytes are a group of algae, and they typically have cell walls made of silica scales.These silica scales can overlap but are not as well-known for forming two thin shells that fit together like the description in the question. Euglenoids:Euglenoids are a group of unicellular protists.They have flexible cell walls made of protein strips beneath the cell membrane. These protein strips do not form two thin overlapping shells that fit together.In summary, among the options given, the group of organisms where cell walls form two thin overlapping shells that fit together is Dinoflagellates.