D can be eliminated because the temperatures where changed in 3 ways, not two.
A is true, but doesn't apply to the actual experiment "design"
B we don't know for sure, it just looks like a cup/glass.
Best answer for you: C
C is true- it was tested with a single independent variable (one that does not change) on multiple trials (the different temperatures)
Answer: it is used primarily in conjunction with surgical anesthesia
Explanation: it is one of the synthetic opioid , it is used intravenously as anesthesia and to treat pain. It is given with a muscle relaxant and a sedative hypnotic. The effect is quick in the body and central nervous system and can last less than 2 hours.
Answer:
some stuff you can just look up on goigle my dude