Which bone marrow type stores fat for energy storage?

• A. Red marrow
• B. Yellow marrow
• C. White marrow
• D. Blue marrow

Answer: (B)

The important idea here is that bone marrow comes in types with distinct roles: red marrow is where blood cells are formed, while yellow marrow stores fat as an energy reserve. Yellow marrow is rich in adipocytes, serving as a fat store that can supply energy when needed. In adults, most marrow is yellow, especially in the long bones, whereas red marrow remains in specific sites like the skull, vertebrae, ribs, sternum, pelvis, and the ends of some bones where hematopoiesis occurs. Under increased demand for blood cells, yellow marrow can convert back to red marrow, but its primary function under normal conditions is fat storage. The terms white marrow and blue marrow aren’t standard classifications for marrow types, so they don’t describe the primary function. Therefore, the marrow type that stores fat for energy storage is yellow marrow.