Question

Pick the wrong statement
(a) Diatoms are primarily produced in the oceans
(b) Diatoms are microscopic and float passively in the water
(c) Walls of diatoms are destructible and easily
(d) Diatomaceous earth is formed by the cell walls of diatoms

Answer 1

Hint:
The cell wall is known as the frustule which is divided into two halves (theca) namely epitheca and hypotheca. There are two basic groups of diatoms- one with radial symmetry (the centric diatoms) and the other with bilateral symmetry (the pinnate diatoms).

Complete step by step answer:
Diatoms (phylum Chrysophyta) are the chief producers (autotrophs) in the oceans. Both marine and freshwater environments are favoured by diatoms and these are found in both. They contain a unique glass-like wall made of hydrated silica(silicon dioxide) embedded in an organic matrix. The cell wall forms two thin overlapping shells, which fit together like a soap box. Also, the walls are embedded with silica so these are indestructible.
They lack flagella, except on some male gametes. Reproduction in diatoms is primarily asexual by binary fission. This form of division results in a size reduction of the daughter cell that received the smaller frustules from the parent and therefore the average size of a diatom population decreases. Sexual reproduction is uncommon. Diatomaceous earth is made from the remains of tiny, aquatic organisms called diatoms. Silica which is a natural substance forms their skeletons. For a large period, diatoms accumulated in the sediment of rivers, streams, lakes, and oceans. Silica deposits are mined today from these areas.

Option ‘C’ is correct

Note:
Diatoms contain photosynthetic pigments chlorophylls a and c and carotenoids, and fucoxanthin. Diatoms' energy reserves are stored as lipids and water-soluble polysaccharide chrysolaminarin in vacuoles. Chrysolaminarin is similar to laminarin found in brown algae.