A Level Biology Practice Exam

What is natural passive immunity?

1. Immunity developed through vaccination

2. Immunity provided by maternal antibodies

3. Immunity acquired by exposure to pathogens

4. Immunity resulting from genetic modification

The correct answer is: Immunity provided by maternal antibodies

Natural passive immunity refers to the transfer of antibodies from one individual to another, providing temporary immunity without the recipient's immune system needing to produce its own antibodies. Maternal antibodies, specifically, are passed from mother to child either through the placenta during pregnancy or through breast milk after birth. This type of immunity is crucial for newborns, as it helps protect them from infections until their own immune system matures and can respond to pathogens effectively. The other options represent different forms of immunity. Immunity developed through vaccination involves actively stimulating the immune system to produce its own antibodies and memory cells against a specific pathogen. Immunity acquired by exposure to pathogens is known as natural active immunity, where the body generates its own immune response after encountering a disease. Immunity resulting from genetic modification refers to engineered changes to an organism's genome to enhance immune responses or produce specific antibodies, which is not a naturally occurring process. Therefore, the correct answer highlights the unique, transient nature of natural passive immunity through maternal antibodies.