Answer:
False,because there are no social animals
False because people don't have to inhale the smoke
Answer:
Starts in a group of cells at the top of your heart called the sinoatrial (SA) node. The signal then travels down through your heart, triggering first your two atria and then your two ventricles. ... The SA node (called the pacemaker of the heart) sends out an electrical impulse.
Explanation: