How many characters are related to diatoms? 

A. Chief producers in oceans.

B. Cell wall is indestructible

C. The deposits of cell wall at the floor of oceans is called kieselghur.

D. They are marine flagellated forms 

Diatoms are non-flagellated planktonic forms of mostly oceans and seas and a little extent in freshwater bodies. They have soap box like indestructible cell wall made of silica which are deposited over ocean floor and known as kieselghur. They are chief producers of oceans.