Since the other answer got deleted, i'll just answer it for you.
a sinoatrial node is the main pacemaker that begins each heartbeat located in the junctions of superior vena cava and the right atrium. It signals from the node that spread through the atria and determines the heart rates.
B) guidelines for safe laboratory practices and policies
Answer: Amoeba are living even though they have one cell
Explanation:
This process is called mitosis
