Final answer:
A heterogeneous mixture is one where the different components are not evenly distributed and can be visibly distinguished. Filings and sand in water is an example of a heterogeneous mixture.
Step-by-step explanation:
A homogeneous mixture is a mixture where the different components are evenly distributed and cannot be visibly distinguished, while a heterogeneous mixture is a mixture where the different components are not evenly distributed and can be visibly distinguished.
Based on this definition, option b) Filings and sand in water is not a homogeneous mixture because the filings and sand particles are visibly different from the water. In this mixture, the filings and sand particles are not evenly distributed and can be seen clearly.
In contrast, option a) Sand and water can be considered a homogeneous mixture because the sand particles are evenly distributed throughout the water and cannot be visibly distinguished.
Learn more about Homogeneous and Heterogeneous Mixtures