Final answer:
The statement that the inner surface of the medulla is folded into projections called renal pyramids is true. These structures are essential for urine formation and are divided by renal columns.
Step-by-step explanation:
The inner surface of the medulla is indeed folded into projections called renal pyramids. The statement that the inner surface of the medulla is folded into projections called pyramids is true. The medulla consists of multiple pyramidal tissue masses, and in between the pyramids are spaces called renal columns. The renal pyramids contain collecting ducts and the loops of Henle of juxtamedullary nephrons, crucial components in the process of urine formation. The renal columns radiate downward from the cortex through the medulla and separate the renal pyramids, while also providing a supportive framework for blood vessels.