<span>Acids will break down the rocks, as the acids goes deep in the rocks cracks can form. When the cracks get to large the rock can break apart.</span>
A heterogeneous mixture composes of non- uniform components, so the concrete would be the answer, because you can tell the components from one another.
As you stated before, cellulose is found throughout the cell walls of plant cells. Cellulose makes cell walls rigid, so that would indicate that cellulose is a carbohydrate.
