Correct option is C
The correct answer is (c) 4
Explanation:
Mammals, including humans, lions, elephants, and whales, have a four-chambered heart. The heart is divided into four chambers to ensure the complete separation of oxygenated and deoxygenated blood, which is crucial for maintaining a high metabolic rate.
The four chambers are:
- Right Atrium – Receives deoxygenated blood from the body.
- Right Ventricle – Pumps deoxygenated blood to the lungs for oxygenation.
- Left Atrium – Receives oxygenated blood from the lungs.
- Left Ventricle – Pumps oxygenated blood to the entire body.
This double circulation system helps mammals maintain a constant body temperature (warm-blooded nature) and ensures efficient oxygen supply to organs.
Information Booster:
- The septum (wall of muscle) divides the left and right sides of the heart, preventing the mixing of oxygenated and deoxygenated blood.
- The heartbeats are regulated by the sinoatrial (SA) node, known as the natural pacemaker of the heart.
- The average resting heart rate of mammals varies:
- Humans: 60-100 beats per minute
- Elephants: 25-30 beats per minute
- Mice: 500-600 beats per minute
Additional Knowledge:
- Amphibians and most reptiles (except crocodiles) have a three-chambered heart with two atria and one ventricle, leading to some mixing of oxygenated and deoxygenated blood.
- Fish have a two-chambered heart consisting of one atrium and one ventricle, where blood is pumped in a single circulatory system.