Homogeneity and heterogeneity are concepts relating to the uniformity in a substance. A material that is homogeneous is uniform in composition or character; one that is heterogeneous is distinctly nonuniform in one of these qualities
A homogeneous mixture has a uniform appearance and composition throughout, even on the particulate level. A homogeneous mixture is also called a solution. Liquid solutions are transparent rather than cloudy. Therefore, tomato sauce is indeed a heterogeneous mixture.