An engineer constructs a model of a new dam that is to be built above the danube river. he uses the same type of cement that will be used on the real dam. the dam design is called arch-22. he tests the miniature cement dam using a pressurized water tank. which predictions could not be made from using a model such as this? a) the arch-22 design may have weaknesses around the base. b) a coating may need to be added to the concrete, as water weakens it. c) the danube river may rise above the level of the dam during spring. d) the arch-22 dam needs to be sloped at 39 degrees, to give maximum strength.