Question

In which group of organisms the cell wall forms two overlapping shells that fill together?
A. Chrysophytes
B. Euglenoids
C. Dinoflagellates
D. Slime moulds

Answer 1

Hint: Chrysophytes come under the kingdom known as Protista. During classification, Protista is known as the kingdom that includes diatoms and desmids (golden algae). Their entire group is almost photosynthetic. The diatoms of this kingdom have a characteristic feature that is, the cell walls form two thin overlapping cells that fit together as in a soapbox.

Complete answer:
> Option (A)- Chrysophytes are microscopic freshwater organisms that float passively in water currents. They are further subdivided into diatoms and desmids. Diatoms have rare cells that form two overlapping shells, which fit together as in a soapbox. Their cell walls are fixed inside of the silica and are perpetual.

> Option (B) - Euglenoids are considered under the algal phylum Euglenophyta in the kingdom Protista. They make up a large group of common microorganisms. They number between 750 and 900 known species. They are found in both fresh and stagnant water. They can also be found in marine habitats.

> Option (C) - The dinoflagellates are single-celled eukaryotes. They constitute the phylum Dinoflagellata. They are usually considered as algae. They are mostly marine plankton, but they also are common in freshwater habitats. The distribution of their population depends on sea surface temperature, salinity, or depth.

> Option (D)- Slime mold or slime mould is an informal name given to several kinds of eukaryotic organisms that are unrelated to each other. They can live freely as single cells or can aggregate together to form multicellular reproductive structures. Slime moulds were classified as fungi in the past but are no longer considered part of that kingdom.

Hence, The correct answer is option (A).

Note: Kingdom Protista consists of eukaryotes and unicellular organisms. They can not be classified as a plant, animal, or fungus because they are unicellular but some algae are multicellular. Kingdom Protista are divided into different groups like chrysophytes, dinoflagellates, euglenoids, and slime molds.