b is the right answer I think
if you or anyone you know is good at math then please go to my profile and check out my question that I need answered
SA Node<span> which is also known as the sinus node, is the natural pacemaker of
the heart. It controls the heart rate by generating electrical impulses
and then sending electrical signals through the heart muscle, causing
the heart to contract and pump blood throughout the body. </span>
The SA Node is located in the outer layer of the right atrium of the heart, near the superior vena cava. It is made up of a group of cells (myocytes) positioned on the
wall of the right atrium, at the center of the heart and near the
entrance of the superior vena cava. These cells contract at a rate of
about 70-80 times per minute, which make up the natural heart beat.
I’m assuming you mean if the sun dies out. If so, then most things on earth would die within a few days due to lack of photosynthesis and to freezing temperatures (which is what would cause humans to die).
If a student rests and then squeezes a clothespin for one minute, will they be able to squeeze it more than someone that exercised before squeezing the pin for 1 minute?
Hope this helps!
