Shell of diatoms is made up of :-

Options

A. Silica
B. Calcium carbonate
C. Keratin
D. Calcium oxalate

Answer

**Step-by-Step Solution:**

1. **Understanding Diatoms**: Diatoms are a group of microalgae known for their unique cell structure. They are a major component of phytoplankton and are found in oceans, waterways, and soils.

2. **Identifying the Composition of Diatom Shells**: The shells of diatoms are not made of typical organic materials. Instead, they have a distinctive composition that is crucial for their survival and functionality.

3. **Correct Option**: The shell of diatoms is primarily made up of **silica**. This silica forms a structure known as a frustule, which consists of two overlapping halves.

4. **Structure of the Frustule**: The frustule is composed of two parts: the **epitheca** (the upper half) and the **hypotheca** (the lower half). This unique structure allows for various adaptations in their environment.

5. **Function of the Frustule**: The frustule not only provides protection but also has tiny pores that connect the protoplast (the living part of the cell) with the external environment, allowing for nutrient exchange and other functions.

6. **Eliminating Incorrect Options**:
- **Calcium Carbonate**: This is found in the cell walls of red algae, not diatoms.
- **Keratin**: This is a protein found in animal tissues such as skin and nails, not in diatoms.
- **Calcium Oxalate**: This is a compound associated with kidney stones in humans and is not a component of diatom shells.

7. **Conclusion**: Therefore, the correct answer to the question is that the shell of diatoms is made up of **silica**.

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