Which of the following is a heterogeneous mixture?

A homogeneous mixture is a mixture where the components that make up the mixture are uniformly distributed throughout the mixture. The composition of the mixture is the same throughout. There is only one phase of matter observed in a homogeneous mixture.

Examples-

-air

-sugar water

-rainwater

-vinegar

A mixture of sand and water is a heterogeneous mixture because it is a mixture with non-uniform composition.