What is the difference between a root crop and a rhizome?

Every plant has a root system. Rhizomes are part of the root system, brown in color, do not have vegetative buds, nodes and internodes; present in all plants. Rhizomes are mainly involved in the absorption of water and minerals from the soil.
Root crops are underground modified stems. They grow on the surface of the earth, with nodes and knots in the form of a stem; brown, have buds of shoots. Root crops are involved in food storage and vegetative propagation.