Final answer:
The spaces between trabeculae in spongy bone are filled with bone marrow.
Step-by-step explanation:
Spongy bone, also known as cancellous bone, contains spaces between trabeculae that are filled with bone marrow. These spaces provide a lattice-like network of support and make the bone lighter than compact bone. Red marrow is found between the trabeculae and is responsible for hematopoiesis, the formation of blood cells.