Mammals have double circulation which means that

Options

A. Heart chambers receive both oxygenated and deoxygenated blood which are completely separated from each other
B. The blood circulates with double speed than other vertebrates
C. There are two types of blood vessels associated to every orgen
D. The blood vessels are paired

Answer

**Step-by-Step Solution:**

1. **Understanding Double Circulation**: Double circulation refers to the system in which blood passes through the heart twice during one complete circuit of the body. In mammals, this means that there are two distinct pathways for blood flow: one for oxygenated blood and one for deoxygenated blood.

2. **Structure of the Heart**: Mammals have a four-chambered heart, which consists of two atria (upper chambers) and two ventricles (lower chambers). The right atrium receives deoxygenated blood from the body, while the left atrium receives oxygenated blood from the lungs.

3. **Separation of Blood**: In mammals, the heart chambers are completely separated, ensuring that oxygenated and deoxygenated blood do not mix. This separation is crucial for efficient oxygen transport and overall metabolic function.

4. **Flow of Blood**:
- Deoxygenated blood enters the right atrium from the body and is pumped into the right ventricle.
- The right ventricle then sends this blood to the lungs via the pulmonary artery, where it is oxygenated.
- The oxygenated blood returns to the left atrium from the lungs and is then pumped into the left ventricle.
- Finally, the left ventricle sends the oxygenated blood out to the rest of the body through the aorta.

5. **Conclusion**: Therefore, the correct interpretation of double circulation in mammals is that their heart has two separate circuits for blood flow: one for oxygen-poor blood and one for oxygen-rich blood, which are completely separated from each other.