Oxygen-rich blood from the lungs comes to the thin-walled upper chamber of the heart on the left. The left upper chamber (A) then relaxes. It then contracts and the blood is allowed to enter the next chamber (B), as it expands. When the muscular left lower chamber of heart contracts the blood is pumped out to the body via aorta.
Deoxygenated blood reaches from the body to the upper chamber on the right side of heart (C) and it expands. As this part contracts, the corresponding lower chamber (D) dilates. This transfers the blood to right ventricle, which in turn pumps it to the lungs for oxygenated.
Which chambers of human heart contain oxygenated blood?

Options

A. A and B
B. A and C
C. C and B
D. C and D

Explanation

To determine which chambers of the human heart contain oxygenated blood, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Chambers of the Heart**:
- The human heart has four main chambers:
- Left Atrium (A)
- Left Ventricle (B)
- Right Atrium (C)
- Right Ventricle (D)

2. **Understand the Flow of Oxygenated Blood**:
- Oxygen-rich blood comes from the lungs and enters the heart through the **Left Atrium (A)**.
- From the Left Atrium, the blood flows into the **Left Ventricle (B)**.

3. **Recognize the Function of Each Chamber**:
- The Left Atrium (A) receives oxygenated blood and then contracts to push this blood into the Left Ventricle (B).
- The Left Ventricle (B) is muscular and pumps the oxygenated blood out to the body through the aorta.

4. **Identify the Chambers with Deoxygenated Blood**:
- Deoxygenated blood returns from the body to the **Right Atrium (C)**.
- This blood then moves into the **Right Ventricle (D)**, which pumps it to the lungs for oxygenation.

5. **Conclusion**:
- The chambers that contain oxygenated blood are the **Left Atrium (A)** and the **Left Ventricle (B)**.

### Final Answer:
The chambers of the human heart that contain oxygenated blood are the **Left Atrium (A)** and **Left Ventricle (B)**.

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