Question 20 When __ become enclosed in lacunae they differentiate and become cells called __ osteoblasts; osteoclasts osteogenic cells; osteoblasts osteocytes; osteoblasts osteoblasts; osteocytes osteocytes; osteoclasts

## Step 1<br />The question is asking about the process of bone formation and the types of cells involved in this process. <br /><br />## Step 2<br />Osteoblasts are cells that are responsible for the formation of new bone. They are derived from osteogenic cells, which are stem cells found in the bone marrow.<br /><br />## Step 3<br />Once osteoblasts have completed their role in bone formation, they become trapped in the bone matrix and transform into osteocytes. Osteocytes are mature bone cells that are responsible for maintaining the bone matrix.<br /><br />## Step 4<br />Osteoclasts, on the other hand, are cells that are responsible for the resorption of bone. They are not derived from osteogenic cells or osteoblasts, but rather from a different lineage of stem cells.<br /><br />## Step 5<br />Given this information, the correct answer is "osteoblasts; osteocytes".