Assertion (A): Veins carry blood away from the heart to different organs of the body.

Reason (R): Veins supply oxygenated blood to most organs of the body except lungs because lungs already contain enough amount of oxygen.

1. Both A and R are true.
2. Both A and R are false.
3. A is true and R is false.
4. A is false and R is true.

Assertion (A): Blood is the fluid medium of the human circulatory system, responsible for transporting nutrients and excretory wastes, but it does not carry oxygen or carbon dioxide gases.

Reason (R): Oxygen and carbon dioxide gases are transported through the lymph vessels from one part of the body to the other since they are in gaseous states.

1. Both A and R are true.
2. Both A and R are false.
3. A is true and R is false.
4. A is false and R is true.

Assertion (A): The walls of the atria are thinner as compared to those of the ventricles.

Reason (R): The atria are the 'receiving chambers' as they receive blood and ventricles are the 'distributing chambers' as they pump blood into lungs and the thickest blood vessel - Aorta.

1. Both A and R are true.
2. Both A and R are false.
3. A is true and R is false.
4. A is false and R is true.

Assertion (A): Capillaries are the finest blood vessels in the body, interconnecting arteries and veins.

Reason (R): The interconnection between arteries and veins is very significant because the exchange of water, nutrients, waste materials and respiratory gases occurs from arteries to veins and vice-versa through the capillaries only.

1. Both A and R are true.
2. Both A and R are false.
3. A is true and R is false.
4. A is false and R is true.