Complimentary angles are the right answer
Hydrofluoric acid is a solution of hydrogen fluoride (HF) in water. Solutions of HF are colourless, acidic and highly corrosive. It is used to make most fluorine-containing compounds; examples include the commonly used pharmaceutical antidepressant medication fluoxetine (Prozac) and the material PTFE (Teflon).
The correct options would be
OPTIONS 1 & 2
The state which a person lives in has nothing to do with the experiment, although it would most likely make it easier to observe. Wheter they develop heart disease or not is the results of the experiment.
