<span>Answer
1. electrical signal travels toward the heart
2. signal by the nodes in the atrium</span>
3. the atria contract<span>
</span>4. signal received by the atrioventricular node
5. signal transferred to the ventricles
6. the ventricles contract
Heart has a pacemaker that will continually send a signal. The primary site of the pacemaker is at the sinoatrial node, on the top right atrium. This node will send a signal to atria (which will cause it to contract) and to the atrioventricular node.
Atrioventricular node located between atrium and ventricle. It will send the signal to the ventricle(by the bundle of his) and cause it to contract.
D., it increases the biodiversity of the species
