Simplify the following text for a Grade 12 native English-speaking person.
Original: College football is American football played by teams of students from different American universities , colleges , and military academies .
Simplified: College football refers to American football played by teams of student athletes fielded by American universities , colleges , and military academies , or Canadian football played by teams of student athletes fielded by Canadian universities . It was through college play that North American football codes first gained popularity in Canada and the United States .