Which Statement About Bone Is True

Which statement about bone is true?

A) Insoluble calcium carbonate crystals are in the extracellular matrix of bone.
B) Calcitonin and thyroxine regulate calcium levels in the bone and extracellular fluid.
C) Time spent in zero gravity causes bones to decalcify, while weight-bearing exercise increases bone deposition.
D) Bone remodeling occurs only while a young person is growing.
E) Bone is devoid of collagen fibers.