(lb). Circle the invalid statement (s) about the control volume: (A) Both the mass and the energy can cross the boundary of a control volume. (B) Under the steady-flow condition,

the volume, mass and energy contents of a control volume remain constant. (C) Under the steady-flow condition, the fluid properties at an inlet or exit always remain constant(do not change with time). (D) Under the steady-flow condition, the intensive properties of the substance contained within system must be homogeneous (uniform) everywhere in a control volume. (E) Gas turbines, throttling valves, nozzles and diffusers operated under steady condition can betreated as the steady-flow control volume system.