The correct answer is A . MIlk is a mixture because pure substances were combined together without formation of bonds, hence it would be easy to separate the substances. On the other hand, salt, sulfuric acid and carbon-dioxide are made from bonding between elements in the periodic table to form compounds. Salt is formed through bonding between Na and Cl atoms, while sulfuric acid [tex]H_2SO_4[/tex] is made from bonding [tex]H^+[/tex] and [tex]SO_4^-^2[/tex] ions. Carbon-dioxide [tex]CO_2[/tex] is made from bonding between C and O elements. Compounds bond at a specific ratio while mixtures have no specific ratio of mixing.
