What is red snow phenomenon ?

Explanation

### Step-by-Step Solution:

1. **Definition of Red Snow Phenomenon**: The red snow phenomenon, also known as watermelon snow, refers to a natural occurrence where snow appears red in color.

2. **Cause of Red Color**: The red coloration of the snow is primarily due to the presence of a specific species of green algae called **Chlamydomonas nivalis**.

3. **Pigments Involved**: The red tint in the snow is attributed to a pigment known as **carotenoid**, which is present alongside chlorophyll in the algae.

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