Answer:
The “lub” is the first heart sound, commonly termed S1, and is caused by turbulence caused by the closure of mitral and tricuspid valves at the start of systole. The second sound,” dub” or S2, is caused by the closure of aortic and pulmonic valves, marking the end of systole.
Dietary,health,stress level,blood pressure,smoking
Permanent damage
1. neurons
2. muscle cells
3. red blood cells
4. sperm cells
5. leukocyte
im not 100% sure but i hope this helps :)
