(50 points)The picture is a cross section of a bone.
A cross sectional view of bone. X points to the inner layer. Y points to the middle layer.
Which structures of the bone are indicated by the arrows?
A. X-compact; Y-spongy
B. X-spongy; Y-marrow
C. X-spongy; Y-compact
D. X-marrow; Y-spongy
