The chief producers in the oceans are:

1. Floating hydrophytes 2. Blue green algae
3. Desmids 4. Diatoms
Subtopic:  Kingdom Protista: Chrysophytes |
 88%
Level 1: 80%+
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The cell walls of diatoms are ‘indestructible’ as they are embedded with:

1. Silica 2. Chitin
3. Calcium 4. Raphides
Subtopic:  Kingdom Protista: Chrysophytes |
 94%
Level 1: 80%+
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