Question

3. What is the nature of cell-walls in diatoms?​

Answer 1

Answer:

The cell walls of diatoms are made of silica. Their cell wall construction is known as frustule. It consists of two thin overlapping shells that fit into each other such as a soap box. When the diatoms die, the silica in their cell walls gets deposited in the form of diatomaceous earth.

Answer 2

Their cell wall form two things overlapping shells which looks like a soap box.

Wall is embedded with silica and thus it is indestructible.

After dying they left behind cell wall deposits and that forms diatomaceous earth. Being gritty, the soil is used in polishing, filtration etc.