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.
The basic repeating unit of nucleic acids are known as nucleotides
Answer:
the citric acid cycle and preparatory steps
What is the question here? There’s multiple answers
