What kind of heart and bones.do birds have?

Explanation

### Step-by-Step Solution:

1. **Heart Structure in Birds**:
- Birds have a **four-chambered heart**. This means that their heart consists of two atria and two ventricles, similar to mammals.
- The four chambers allow for the complete separation of oxygenated and deoxygenated blood, which is crucial for efficient oxygen delivery to the body.

2. **Function of the Heart**:
- The separation of blood in the heart enables birds to maintain a high metabolic rate, which is essential for activities such as flying.
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