Question

Diatoms do not decay easily because

• A. They have siliceous walls
• B. Their body is impervious to water
• C. They are chitinous
• D. They are abundant in saline soil

Answer 1

The correct option is A They have siliceous walls

Diatom cells are contains a unique silica cell wall, comprising two separate valves or shells. The biogenic silica that the cell wall is composed of is synthesised intracellularly by the polymerisation of silicic acid monomers. This material is then extruded to the cell exterior and added to the wall. Diatom cell walls are also called as frustules. The silica of the diatom cell wall is resistant to decay, although it will begin to dissolve once its organic coating has been stripped off. Once incorporated into silica-rich sediments, however, frustules may survive for hundreds to millions of years and can be used to monitor changes in freshwater or marine environments.

Thus, the correct answer is option A.