Answer:
The answer to your question is a heterogeneous mixture
Explanation:
The Matter is classified as Pure substances and Mixtures
Pure substances are elements or compounds which are not mixed with more substances.
Mixtures are several elements or compounds together, mixtures can be homogeneous or heterogeneous.
Homogeneous mixtures are when the different components can be identified.
Heterogeneous mixtures are when the different components can be identified just by looking at the mixture.
In concrete we can identify the different components like gravel, sand, crushed rocks, etc, so concrete is a heterogeneous mixture.
