Ok so O3 has a greater electronegativity and is taken into account first, -2*3=-6, so As has to equal 6/2=3, so As has a +3 oxidation number here
I would say they design and build things.
Answer:
B. It tells whether products or reactants are favored at equilibrium.
Opioid's tend to show during runners high, so my guess would most likely be dopamine