Identify the force preventing u. s. professionals from extending their practices on the web.

Ray gives his son, mason, three bowls. these bowls have the same capacity, but each one differs slightly in its shape and size. ray tells his son that one of the bowls can hold more liters of oil than the other two bowls. mason points out that all the bowls, though may appear different in size and shape, can store the same volume of oil. in this case, ray was most likely testing mason's concept of