Final answer:
The fact that the body does not normally mount an immune response to the molecules in food is an example of immune tolerance.
Thus option a. is correct answer.
Step-by-step explanation:
Immune tolerance is the body's ability to prevent an unnecessary or harmful immune response to non-threatening substances like food proteins, involving the critical role of regulatory T cells in this regulation.
This is the acquired ability to prevent an unnecessary or harmful immune reaction to a harmless foreign particle, such as a food protein.
When an individual has an allergy, their immune system incorrectly identifies a harmless protein, typically from the environment, as a threat and mounts an immune response against it, which causes the range of symptoms associated with allergies.
Immune tolerance is critical because it allows the immune system to focus on genuine threats, like pathogens, without responding to non-threatening substances such as food or self-antigens. Regulatory T (Treg) cells have a crucial role in this process, as they help to suppress local inflammation and prevent the activation of the immune system in cases where it is not required. Problems with immune tolerance can lead to allergies or autoimmune diseases.
Thus option a. is correct answer.