[" A pure substance can only be "],[" A a compound "],[" (B) an element "],[" (D) a homogenous mixture "]

Pure substance can be

Which of the following statement is/are correct? (i) An element of a substance contains only one kind of atoms. (ii) In CO2, carbon and oxygen chemically combined in a fixed proportion of 3 : 8 by mass. (iii) The constituents of the pure substances can be separated by simple physical methods. (iv) Milk is a homogeneous mixture.