Question

when blood calcium levels are low, how do the bones respond?
a osteoclast activity is stimulated, weakening the bones.
b osteoclast activity is stimulated, strengthening the bones.
c osteoclast activity is inhibited, weakening the bones.
d osteoclast activity is inhibited, strengthening the bones.

Explanation:

When blood calcium levels are low, the body needs to increase calcium in the blood. Osteoclasts break down bone (which contains calcium) to release calcium into the bloodstream. Stimulating osteoclast activity would lead to bone breakdown (weakening the bones in the process of getting calcium for the blood).

Answer:

A. Osteoclast activity is stimulated, weakening the bones.