What lymphocyte secretes antibodies to defend the body against antigens and pathogens in body fluids? A. B cells B. T cells C. Active D. NK cells

Break Down the Problem

1. Identify the types of lymphocytes given in the options.
2. Understand the functions of each type of lymphocyte in relation to antibodies and pathogen defense.

Relevant Concepts

1. B cells: These lymphocytes are responsible for producing antibodies.
2. T cells: These cells do not secrete antibodies; instead, they help regulate immune responses and kill infected cells.
3. Active: This is not a type of lymphocyte; it may refer to an active form of immune response.
4. NK cells (Natural Killer cells): These are involved in the direct killing of infected cells but do not produce antibodies.

Analysis and Detail

1. B cells: Upon activation, B cells differentiate into plasma cells that secrete antibodies into body fluids.
2. T cells: Primarily involved in cell-mediated immunity.
3. Active: This term is vague without context.
4. NK cells: Part of the innate immune system; they do not respond to antigens in a specific manner.

Verify and Summarize

Among the options, B cells are the only lymphocytes that secrete antibodies, providing specific defense against antigens found in body fluids.

Final Answer

A. B cells