Question

Birds and mammals have:

• A. Single and closed type circulation
• B. Double and open type circulation
• C. Double and closed type circulation
• D. Single and open type circulation

Answer 1

The correct option is C Double and closed type circulation

Birds and mammals have four-chambered hearts. Their circulatory system is called the double circulatory system because blood passes through the heart twice:

Body $\to$ Heart $\to$ Lungs $\to$ Heart $\to$ Body

Birds and mammals have a closed type of circulation wherein the blood does not directly come in contact with the cells or tissues but instead flows in tube-like structures called the arteries, veins, and capillaries.

So, the correct answer is option C.