_______ are green-coloured plastids.

Explanation

**Step-by-Step Solution:**

1. **Identify the Type of Plastids**: The question asks for a specific type of plastid that is green in color. Plastids are organelles found in plant cells, and they come in different types based on their function and color.

2. **Recognize the Green Plastid**: Among the various types of plastids, the one that is specifically green is known as chloroplast.

3. **Function of Chloroplasts**: Chloroplasts are primarily responsible for photosynthesis, the process by which plants convert light energy into chemical energy.

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