Afarmer had an accident and spilled a chemical into his pond. several days later, he notices many dead frogs around the pond. that summer, the number of gnats around the pond was higher than ever. this is because

The frogs are a limiting factor for the gnats.

clinically, some people often have repeated allergies, eczema and respiratory infections or other parts of the infection, in this case, in addition to some routine tests such as tests for white blood cells, immunoglobulin series, lymphocyte subsets, etc., the five immune immunoglobulin tests are also necessary.