I believe the first one you must talk to should be your mom or dad.
Answer:
a. QRS
Explanation:
In Human anatomy, cardiac cycle can be defined as a complete heartbeat of the human heart which comprises of sequential alternating contraction and relaxation of the atria and ventricles, therefore causing blood to flow unidirectionally (one direction) throughout the human body.
Generally, the cardiac cycle occurs in two (2) stages;
Diastole : in this stage, the ventricles is relaxed and would be filled with blood.
Systole: at this stage, the muscles contracts and thus, allow blood to be pushed through the atria.
The right atrioventricular valve (AV) comprises of three (3) leaflets (flaps) which opens and closes in order to allow for the flow of blood from the right atrium of the human heart to the right ventricle. Also, the right atrioventricular valve is saddled with the responsibility of preventing blood from flowing backward in the mammalian heart.
The QRS complex represents the time necessary for the impulse to travel through the bundle of His, the bundle branches, and the Purkinje fibers to complete ventricular activation or contraction, known as ventricular depolarization. QRS is simply a combination of the Q-wave, R-wave and the S-wave which represents electrical impulses.
The risk of infectious disease might be high in a community that has no water treatment facility because gems spread faster through water , most viruses also are usually spread faster on untreated water.
Well, I'm no expert but U can try baking soda and hydrogen peroxide... mix them up and then swish in your mouth. but dont do it 2 often, because those are both very acidic! Hope I helped