Match the engines in the following list with their drawbacks. Place your answer in the blank space given. i. gunpowder engine ii. Savery engine iii. Newcomen engine iv. Watt engine a.____ The boiler could not withstand the steam pressure needed to lift water beyond 6 m. b.____ The engine had no mechanism to move the piston back to complete a cycle. c.____ The continual reheating needed after each cooling of the engine cylinder required a tremendous amount of thermal energy. d.____ This engine was large and massive and less efficient than thought possible.