The best way may be is going over the notes on the chapter you were doing. Or going over the chapter once or twice.
Answer: https://www.wwf.org.uk/learn/wildlife/polar-bears#:~:text=Challenges%20affecting%20polar%20bears&text=The%20Arctic%20is%20warming%20about,ice%20to%20raise%20their%20young.
https://www.carbonbrief.org/polar-bears-and-climate-change-what-does-the-science-say
Explanation:
Because the AV node takes on the role of a very important delay in the cardiac conduction system. Without this delay, the atria and ventricles would contract at the same time.
<h3>Cardiac conduction system</h3>
The conduction system of the heart sends electrical signals, usually generated by the sinus nodes, causing the heart muscle to contract. Pacemaker signals originating from the sinus node travel through the right atrium to the atrioventricular (AV) along the bundle of His and through branches of the bundle, causing myocardial contraction. This signal first stimulates contraction of the right and left atria then flows to the right and left ventricles. That electric current then allows blood to be pumped throughout the body.
Learn more about sequence of travel by an impulse through the cardiac conduction system at brainly.com/question/28269433
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