THE BRONX - Students at the Academy of Mount St. Ursula traded in chips for apples and soda for water today as part of a crash course in healthy eating.The students are taking part in an eight-week health challenge called the Bronx CAN Initiative, sponsored by state Sen. Gustavo Rivera (D-The Bronx). Some students said they would take the lessons they're learning home to their families.One member of the student government pledged to do what she could to make healthy options available in school vending machines.