Code 74420 for urography, retrograde, with KUB

For a patient who is bleeding, which of the following is the immediate response of the human body?

A) Vasoconstriction caused by the parasympathetic nervous system B) Increased production of red blood cells and hemoglobin C) Vasoconstriction caused by the sympathetic nervous system D) Increased pulse pressure to promote better circulation of oxygen

Which of the following prefixes means "half"?

semi- ultra- bi- epi-