Diatoms are also called as 'pearls of ocean' why ? What is diatomaceous earth ?

Explanation

### Step-by-Step Solution:

1. **Understanding Diatoms**: Diatoms are a type of algae that belong to the group called chrysophytes within the kingdom Protista. They are microscopic and primarily aquatic.

2. **Role in the Ecosystem**: Diatoms are known as the "pearls of the ocean" because they are primary producers in marine ecosystems. They perform photosynthesis, creating food not only for themselves but also for a variety of marine life, including fish and other organisms. This makes them essential for the oceanic food web.

3. **Siliceous Shells**: The bodies of diatoms are unique because they are encased in a hard, siliceous shell known as a frustule. This shell is made of silica and gives diatoms their characteristic shapes and forms.

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