Concept:Monocot and dicot roots differ mainly in internal anatomy, especially in the presence of a wide pith and cambium.
Explanation:A monocot root has a large, well-developed pith at its centre.
A dicot root has only a very small pith or no pith at all.
Cambium is usually absent in monocot roots but present in dicot roots, so option B is not correct.
Endodermis and root hair are found in both monocot and dicot roots, so options A and D are not distinguishing features.
Thus, the characteristic feature that makes a monocot root different from a dicot root is the presence of a wide pith.
Answer:C. wide pith