Why are red tides caused and why are they harmful ?

Explanation

### Step-by-Step Solution:

1. **Definition of Red Tides**:
- Red tides are a phenomenon characterized by the discoloration of coastal waters due to the rapid multiplication of algae, known as algal blooms.

2. **Causes of Red Tides**:
- Red tides are primarily caused by algal blooms, which occur when certain species of algae grow excessively in response to favorable environmental conditions such as nutrient-rich waters, warm temperatures, and sunlight.

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