The leading cause of "hay fever" in early summer are commonly which of the following?

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Quizplus · Accepted Answer

Grasses are a common cause of hay fever in early summer, typically in May and June in many areas. Molds can also cause allergic reactions, but they are more common in humid conditions and may be a greater source of irritation later in the summer or in the fall. While angiosperm trees, weeds, and conifers can all cause allergies, they are typically more problematic in other seasons.

The Leading Cause of "Hay Fever" in Early Summer Are