Answer:
(see below)
Explanation:
12. Vena Cava
The top one is the superior vena cava and the bottom one is the inferior vena cava.
13. Right Atrium
14. Valve
This is the atrioventricular (tricuspid) valve.
15. Right Ventricle
16. Pulmonary Artery
These are the left pulmonary arteries.
17. Pulmonary Vein
These are the left pulmonary veins.
18. Left Atrium
19. Left Ventricle
20. Aorta
