An injury that does not involve penetration or fracture of the bones of the skull but results from an external blow or from the brain being whipped back and forth rapidly is which of the following?

the dark variety, as they are not visible on the dark tree barks

explanation:

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)]