(I) Gases mix evenly without the help of any mechanical change. The huge gap between molecules gives the molecules of other elements an ease to mix with each other. Thus statement (I) is correct. (II) The molecules in a gaseous element scatter by forces in all direction due to the negligible force of attraction between them. Therefore. the molecules exert pressure in all directions. Hence, statement (II) is correct. (III) Gases are highly compressible. As the molecules in gaseous elements are scattered at a large distance as compared to the other two states (solid and liquid), these are highly compressible. Hence, statement (III) is correct. (IV) Gas is a state of matter that has no fixed shape and no fixed volume. Thus, statement (IV) is incorrect. Therefore, statement I, II and III are correct but statement IV is incorrect and hence, option (c) is correct.