Which type of immunity is acquired when an individual receives preformed antibodies against a specific pathogen?

Explanation: B cells recognize antigens by producing specific receptors on their cell surface, known as antibodies or immunoglobulins. When a B cell encounters an antigen that matches its specific antibody, it binds to the antigen, marking it for destruction or neutralization by other immune cells.

Incorrect choices:

a. Engulfing and processing pathogens is the role of antigen-presenting cells like macrophages and dendritic cells. These cells present processed antigens to other immune cells, including B cells, to trigger an immune response.

b. Cytokines are small proteins that serve as signaling molecules in the immune system. They are produced by various immune cells to regulate immune responses, but they are not directly involved in antigen recognition by B cells.

d. Directly attacking and killing infected cells is the role of cytotoxic T cells during cell-mediated immunity, not B cells during the humoral immune response.

Explanation: The immune response is a complex system of defense mechanisms that aim to protect the body from pathogens, such as bacteria, viruses, and other foreign substances. It involves the activation of various immune cells, production of antibodies, and other immune components to recognize and eliminate the invading pathogens.

Incorrect choices:

a. Directly attacking and killing infected cells is the role of cytotoxic T cells during cell-mediated immunity, but it is not the primary purpose of the overall immune response.

b. Antigens are foreign substances that trigger the immune response. They are not produced by the immune response itself but rather recognized by immune cells and antibodies.

c. The immune response is not involved in regulating the body's metabolism. Metabolism regulation is primarily controlled by other systems in the body, such as the endocrine system.