
Topics:
Circulation and Excretion Prokaryotic Cells and Viruses Special Senses HCMA - Hematology Cancer & Cell Cycle Cell Division Circulatory & Lymphatic Trichology Gaseous Exchange in Humans All About Bacteria Year 7 Nutrition Contemporary Nutrition Issues Histology - Tissues Diabetes Cell Cycle ProblemsOther quiz: Heart Anatomy
Un-oxygenated blood enters the right atrium from the top of the heart.
A. inferior vena cava
B. superior vena cava
C. aorta