Count sheep, count down or count up... or just clear your mind whilst looking at a single spot on your ceiling.
Yes, as it can help out in sticky situations. For example, out hiking and a snake bites you, you will know how to limit the poisoning.
bone marrow <span>contains hematopoietic stem cells, which give rise to the three classes of blood cells that are found in the circulation: white blood cells (leukocytes), red blood cells (erythrocytes), and platelets (thrombocytes)</span>
