Final Answer:
In modern, industrialized countries, the most common function of IgE is its role in allergic responses. When exposed to an allergen such as pollen, the body makes IgE antibodies.
Step-by-step explanation:
Function of IgE:
The correct option is "allergic responses," as IgE antibodies play a crucial role in allergic reactions. When the body encounters an allergen, such as pollen, IgE antibodies are produced as part of the immune response.
Role in Allergic Responses:
IgE antibodies are specialized in triggering allergic reactions. Upon exposure to an allergen, IgE antibodies attach to mast cells and basophils, leading to the release of inflammatory substances like histamines. This process results in the typical symptoms of allergies, such as sneezing, itching, and swelling.
Relation to the Given Context:
The blank is filled with "allergic responses," directly aligning with the context of the sentence, which discusses the function of IgE in the context of industrialized countries and their common health challenges related to allergies.
Connection to Exposure to Allergens:
The statement emphasizes that when the body is exposed to an allergen, IgE antibodies are produced. This is consistent with the well-established mechanism of IgE response to specific allergens.
In summary, the most fitting completion for the given sentence is "allergic responses," as it accurately reflects the role of IgE in responding to allergens in industrialized countries.