Option 1: This statement is correct. A mixture does show the properties of its constituents, meaning that the characteristics of each component remain unchanged when they are mixed.

Option 2: This statement is correct. A mixture can be either homogeneous or heterogeneous, depending on whether its components are evenly distributed or not. In contrast, a compound is always a homogeneous substance, meaning that its components are uniformly dispersed.

Option 3: This statement is correct. The constituents of a mixture can be separated by physical methods, such as filtration or evaporation. On the other hand, the constituents of a compound cannot be separated by physical methods. They can only be separated through chemical reactions.

Option 4: This statement is incorrect. Energy can be either absorbed or evolved during both the preparation of a mixture and a compound. For example, when a mixture is formed by dissolving a solid in a liquid, energy is usually absorbed. Similarly, during the preparation of a compound through a chemical reaction, energy may either be absorbed (endothermic) or evolved (exothermic).

Alert - Correct answer should be: None. All the statements provided are correct.