C. to reveal the importance of physical fitness to the Lin family
Explanation:
At first, Mrs. Lin will not allow her daughter to wear jeans, making her wear a skirt. Eventually Mom bought her jeans, her brother made the baseball team, her Mom discovered rummage sales, and her father started taking driving lessons as the family had no car-all signs that the Lin family are discovering the American way of life and adapting.
a control variable is a variable or an element wich is held constant throughout an experiment o a research in order to assess the relationship between multiple variables.
