Why does the heart of man become 2-chambered and 3-chambered before becoming 4-chambered?

Explanation

### Step-by-Step Solution:

1. **Understanding the Evolution of the Heart**:
- The evolution of the heart in vertebrates is a gradual process that reflects the complexity of organisms over time. It started from simple structures and became more complex as organisms evolved.

2. **Single-Chambered Heart**:
- The most primitive heart structure is found in organisms like Amphioxus, which has a single chamber. This heart lacks distinct auricles and ventricles, serving as a basic pump for blood circulation.

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