Main idea: In a solar eclipse the moon blocks out the sun. Which of the following details supports the main idea?
A.
A solar eclipse is magnificent.
B.
The atmosphere of the sun is called the corona.
C.
The moon casts a shadow on the earth.
D.
The moon casts a shadow on the sun.

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)]