What is a compound?
a- a substance in which the atoms of two or more elements are combined together b-an atom with more neutrons than protons
c- a substance in which the atoms of three or more elements are combined together
d- an atom with more electrons than protons

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)]

sorry, is there a picture? i do not see any arrows.

wut? unius0123 wut?