The cells of the SA node at the top of the heart are known as the pacemaker of the heart because the rate at which these cells send out electrical signals determines the rate at which the entire heart beats (heart rate). The cells that create these rhythmic impulses, setting the pace for blood pumping, are called pacemaker cells, and they directly control the heart rate. They make up the cardiac pacemaker, that is, the natural pacemaker of the heart. Hope this helps!
Answer:
There aren't many tips that can be given this late (exercise is something you get better at doing over time), but I can say this:
Breath IN through your mouth, and OUT through your nose. This helps keep your oxygen levels higher so you don't run out of energy.
Don't over-exert yourself in the beginning. Humans are 'endurance predators', so it's bad to run as hard and fast as you can in the beginning because you will drain your energy too soon.
The answer is A) plaque in the arteries can make it difficult for blood to pass through
0.05x+2.99=10.89
subtract 2.99 from both sides
0.05x=7.9
divide each side by 0.05
x=158
Naomi purchased 158 songs.
