Answer:
silicon dioxide is the correct answer.
Step-by-step explanation:
Diatoms are the unicellular algae, found in waterways, soil, and ocean.
diatoms cell walls are made up of silica dioxide which is called frustule because the cell wall is composed of silicon dioxide it makes the cell wall diatoms transparent, which helps them to produce more foods.
As the diatoms cell wall is composed of silica it is used as a silica source, to treat constipation and cholesterol level and also to improve the health by removing the dead cells.