Answer:
The microscopic structural unit of compact bone is called an osteon, or Haversian system. Each osteon is composed of concentric rings of calcified matrix called lamellae (singular = lamella).
Explanation:
The lymphatic system destroy harmful substances 'By producing antibodies'.
The lymphocytes contained in lymphatic organs are produced with other defence cells by the bone marrow. They are then dispersed to eliminate pathogens.
So by looking at the seismic waves from earthquakes the scientist learned about the crust and the mantle but they also learned about the outer and inner core. To do this you have to look at a different kind of waves, the S (secondary waves) waves that also get released by an earthquake.
