Practice question

Chrysophytes, which include diatoms and golden algae (desmids), have unique cell walls forming two thin overlapping shells that fit together. According to NCERT, these walls are heavily embedded with silica, making them practically indestructible. Over billions of years, diatoms leave behind large amounts of these silica cell wall deposits in their habitat, which accumulates to form gritty 'diatomaceous earth', used commercially in filtration and polishing.