Which one of the following statements about mixtures is correct [2] [3] the different substances in a mixture are always in a definite proportion to cacho a mixture is made up of elements that are chemically combined it is extremely difficult to separate a mixture into different substances a mixture must contain at least two different substances a mixture is always homogeneous.

Option (4) is the correct answer.

Explanation:

A mixture is defined as a substance that contains two or more different substance that are physically mixed with each other.

If solute particles are evenly distributed in a solvent then it is known as a homogeneous mixture.

For example, salt dissolved in water is a homogeneous mixture.

If solute particles are unevenly distributed into the solvent then it is known as a heterogeneous mixture.

For example, sand in water is a heterogeneous mixture.

Thus, we can conclude that the statement a mixture must contain at least two different substances, is correct about mixtures.

altitude, density, pressure

air gets less dense the higher the altitude and also the air pressure is less as altitude rises.

a patient chooses to not take a beneficial medical treatment.

explanation: