Answer:
determining why a problem behavior occurs
The correct answer for your question would be, C
Blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. As the atrium contracts, blood flows from your right atrium into your right ventricle through the open tricuspid valve.
C..................................................................................................is your answer
Nitrogenous organic compounds that consist of large molecules
