Which is true about shield volcanoes? A. Gradual slope, relatively gentle eruptions
B. Steep slope, caldera present, violent eruptions
C. Always form underneath the ocean
D. Always form on land

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)]