Which of the following vaccines is typically recommended for adolescents to protect against certain types of cancer?

Explanation: Memory cells recognize and respond rapidly to previously encountered pathogens. Memory cells are a type of immune cell that are formed after an initial infection or vaccination. They "remember" the specific pathogen and allow the immune system to mount a faster and stronger response upon subsequent exposures to the same pathogen, providing long-term immunity.

Incorrect choices:

a. Memory cells do not directly attack pathogens in the body. They serve as a form of immune "memory" to help the body respond more effectively to future infections.

b. Memory cells do not produce antibodies upon initial pathogen exposure. B cells are responsible for producing antibodies in response to the pathogen.

d. Memory cells do not regulate the body's temperature during an infection. Temperature regulation is mainly controlled by the hypothalamus in the brain in response to infection or other stimuli.

Explanation: Passive immunity is the temporary immunity that is acquired from an external source, such as the transfer of antibodies from a mother to her baby through the placenta during pregnancy or through breastfeeding. This type of immunity provides immediate protection but does not result in the production of memory cells.

Incorrect choices:

a. The body's response to a vaccine is an example of active immunity, where the body produces its own antibodies in response to exposure to a weakened or inactive form of a pathogen.

c. The activation of T cells in response to an infection is part of the body's adaptive immune response, contributing to active immunity.

d. The production of memory cells after exposure to a pathogen is also a characteristic of active immunity, as it allows the body to recognize and respond more quickly to future infections with the same pathogen.