Question

activating which bone cell causes the release of protein - digesting lysosomal enzymes and several acids? osteoclasts osteoprogenitor cells osteocytes osteoblasts

Explanation:

Osteoclasts are responsible for bone - resorbing activity. They release protein - digesting lysosomal enzymes and acids to break down the bone matrix. Osteoprogenitor cells differentiate into other bone cells but do not release these enzymes. Osteocytes are mature bone cells with a role in bone homeostasis, not in releasing these enzymes. Osteoblasts are involved in bone formation, not in releasing protein - digesting lysosomal enzymes and acids for bone resorption.

Answer:

Osteoclasts