Assertion (A): Lymphocytes produce antibodies and are the smallest of WBCs with a single large nucleus.

Reason (R): Lymphocytes contain granules in the cytoplasm. Lymphocytes release histamine.

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): Thrombin is the inactive form of prothrombin which is produced during blood coagulation.

Reason (R): Vitamin K, a fat-soluble vitamin, is essential for the production of prothrombin.

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): Kidneys eliminate urea and water only during excretion.

Reason (R): Urea is the most poisonous, nitrogenous waste of the body, so it must be excreted out as early as possible.

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): Renal artery carries deoxygenated blood full of nitrogenous wastes.

Reason (R): Most of the arteries carry oxygenated blood, but there are exceptions.

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.