[Aracne]

Red zone: <50%
Yellow zone: 50-79%
Green zone: 80% and up
Remember that the 100% represent the BEST PEF, not the normal.
When you go to the doc you are asked to do the test multiple times and pick the highest value you get among the attempts, not an average or a intermediate value.
Now, after a while, your asthma symptoms may regress and can achieve a PEF that is actually 115% of the last best value, in this case I assume the 115% will replace the old best value from that point on and will become the 100%.
I honestly didnot study what the average pef is but I doubt it's 200
I think it's between 4-6 liters, I don't think an elephant has lungs capable of containing 200L of air. 200ml seems more the pef of a cat, but I may be wrong. I am surprised they asked how the PEF, RV, FEV are calculated, I really do not know that. I also cheched the APHA, prontopass and CPR, they don't say. And the whistle is to make sure you donot inhale too fast, if you do it whistles and you know you are inhaling too fast.
As for the Ca question, I recall from studying the prontopass that Ca Carbonate has 40% of elemental Ca, 21% for Ca Citrate and 25% for Ca Acetate. Having this info would be enough to answer this question, but if they ask about Mg or Al salts I would be lost too, not going to study the elements' table.
Sulfacetamide is famous for stinging in the eye and even though it's a solution, it needs shacking, remember that it sounds like a carbonic anidrase inhibitor but it's instead an antibiotic. Other stuff, don't touch the dropper with dirty hands, remove contact lenses, avoid other eye drops at the same time, and apply drops to the corner of the eye (near nose) while looking upward.
Man.. that's a nasty exam!