Answer: The right answer is D. all of the above.
Answer:
There is more than one kind of white blood cell
Explanation:
there is more than one type of white blood cells, for example Neutrophils normal percentage 40 to 60%, Lymphocytes 20 to 40%, and Monocytes 2 to 8%
Answer:
a. in the bottom of the atrium just above the ventricles
Explanation:
AV node -
It helps to control the heart rate , it serves as an electrical relay station , reduces the electrical current which is sent by the SA node .
The location of the AV node , is at the lower back section of the inter atrial septum , and conducts the electrical impulse normally from the atria to ventricles .
