Question

yellow bone marrow is useful as_________.
answer
a red blood cell reserve
a calcium reserve
a cartilage reserve
a tissue that may revert back to red bone marrow if a person needs more red blood cells
i dont know yet

Explanation:

Yellow bone marrow consists mainly of fat cells. In cases of severe blood loss or increased demand for red blood cells (such as in certain diseases or after significant blood loss), yellow bone marrow can convert back to red bone marrow (which is responsible for red blood cell production). Red blood cells are produced in red bone marrow, not stored in yellow bone marrow. Calcium is mainly stored in the bone matrix, not in yellow bone marrow. Cartilage has its own growth and maintenance mechanisms and is not related to yellow bone marrow in terms of being a "reserve".

Answer:

a tissue that may revert back to red bone marrow if a person needs more red blood cells