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Grade 12th passBotany

bivalved siliceous shells or frustule occur in
  1. diatoms
  2. radiolarians
  3. zooflagellates
  4. archaebacteria

Profile image of raghav
11 Years agoGrade 12th pass
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1 Answer

Profile image of Apoorva Arora
11 Years ago
The correct option is 1.
Diatoms are a major group of algae, and are among the most common types of phytoplankton. Most diatoms are unicellular, although they can exist as colonies in the shape of filaments or ribbons (e.g. Fragilaria), fans (e.g. Meridion), zigzags (e.g. Tabellaria), or stars (e.g. Asterionella). Diatoms are producers within the food chain. A unique feature of diatom cells is that they are enclosed within a cell wall made of silica (hydrated silicon dioxide) called a frustule. These frustules show a wide diversity in form, but are usually almost bilaterally symmetrical, hence the group name.