Chapter 37, Problem 21A

Summary Introduction

Introduction:

Lymphocytes are B and T cells. They provide immunity for future invasions of bacteria, viruses, and parasites by producing antibodies that have memory and protects against such antigens.

Answer to Problem 21A

Correct answer:

The correct answer is option (A) bone marrow.

Explanation of Solution

Explanation/justification for the correct answer:

Option (A) bone marrow. The lymphocytes are white blood cells that are produced from the stem cells in the bone marrow. Lymphocytes are B and T cells. They provide immunity for future invasions of bacteria, viruses, and parasites by producing antibodies that have memory and protects against such antigens. So, the correct answer is option (A).

Explanation for incorrect answer:

Option (B) thymus gland. The function of the thymus is to receive immature T cells that are produced in the red bone marrow and train them into functional and mature T cells that attack only foreign cells. So, this is an incorrect option.

Option (C) spleen. The spleen is the largest organ in the lymphatic system that is an important organ for keeping bodily fluids balanced. So, this is an incorrect option.

Option (D) lymph nodes. The lymph nodes are the part of the lymph system that carries lymph fluid, nutrients and waste material between the body tissue and the blood stream. So, this is an incorrect answer.