Compare diagram b to diagram a. how is it different?

answer; ///i believe the correct answer is (aids) acquired immune deficiency syndrome;

the answer to your question is slate

answer : haversian

[explanation: -(compact bone is organized as parallel columns, known as haversian systems, which run lengthwise down the axis of long bones. these columns are composed of lamellae, concentric rings of bone, surrounding a central channel, or haversian canal, that contains the nerves, blood vessels, and lymphatic system of the bone)]