A mother is frustrated that her 2-year-old daughter keeps developing ear infections. "I don't understand. Her older brother seldom has any. Why does she have so many

Not enough information for a definitive diagnosis.

Explanation:

There could be a number of reasons that her daughter has chronic ear infections.

However, the most common cause of chronic ear infections in toddlers is  buildup of fluid and mucus behind the eardrum, which does not drain properly through the ear's Eustachian tube.