Answer
(a) water changes from solid to liquid and from liquid to gas.
(b) solid water is sublimed to gas.
Work Step by Step
(a) We know that if the temperature of the system is increased and the pressure is constant, then the water changes from a solid to a liquid and then from a liquid to a gas.
(b) We know that if the temperature of the system is kept constant and the pressure is decreased then the solid water that is ice is sublimed to gas.