An aquatic microscopic organism floats passively with plankton and possesses two overlapping silica-containing wall laye
Diatoms are photosynthetic plankton and are described as chief producers in oceans. Their silica-containing walls accumulate to form diatomaceous earth, which is used in polishing and the filtration of oils and syrups.
Ref: NCERT Class 11 Biology Chapter 2: Biological Classification Protista - Chrysophytes and Dinoflagellates