moving something is a kind of function & webbed feet are used for moving faster through water by aquatic animals ->  the function of webbed feet is to move aquatic animals through water faster  moving faster is a kind of method for moving better & helping means something can be done better ->  helping something move can mean causing something to move faster  the function of webbed feet is to move aquatic animals through water faster & helping something move can mean causing something to move faster ->  the function of webbed feet is to help aquatic animals move through water  the function of webbed feet is to help aquatic animals move through water & swimming is when animals can move in water -> the function of webbed feet is to help aquatic animals swim