where are blood cells made? Periosteum Yellow marrow Spongy Bone Red marrow

## Step 1<br />Blood cells are produced in a process called hematopoiesis. This process takes place in the red bone marrow, which is found in the interior of certain bones.<br />## Step 2<br />The red bone marrow contains stem cells that can differentiate into various types of blood cells. These include red blood cells, white blood cells, and platelets.<br />## Step 3<br />The other options provided, such as the periosteum, yellow marrow, and spongy bone, are not directly involved in the production of blood cells.<br />## Step 4<br />The periosteum is a membrane that covers the outer surface of all bones, except at the joints of long bones. It is involved in bone growth and repair but not in blood cell production.<br />## Step 5<br />Yellow marrow is primarily composed of fat cells and does not play a role in hematopoiesis.<br />## Step 6<br />Spongy bone, also known as cancellous bone, is a porous type of bone found at the ends of long bones and in the interior of other bones. It provides structural support and houses bone marrow, but it is not the site of blood cell production.