When calcium levels in the blood are too low, the body releases a hormone that removes calcium from the bones. A person who suffers from a certain type of thyroid disease will often have low blood calcium and brittle bones because
the body is taking the calcium from the bones. The afflicted person will typically see an endocrinologist, who studies
hormones, and an orthopedist, who studies bones. What do these two doctors have in common?

A) They both focus on hormone levels.

B) They both focus on bone density.

C) They both focus on calcium levels.

D) They both focus on the thyroid.