Helium is a real gas also. The only difference I know is that it is inert and does not interact... Same goes with all the Group 8 Noble gases.
Answer:
Arteries carry blood low in oxygen from the right side of the heart to the lungs to be oxygenated. Blood high in oxygen enters the left side of the heart in the pulmonary vein and is pumped into the systemic circuit.
The answer is C. Ultraviolet light cannot be perceived by the eyes neither can Infrared or Gamma light.