flyfly4, for your carburettor question did you look at the explanation? As altitude increases the air becomes less dense, less mass of air requires less fuel to maintain the mixture.
Concerning 210754 the question is:
"Which of these statements about a reaction turbine are correct or incorrect?
I. The pressure drops slightly across the nozzle guide vanes.
II. The pressure remains constant across the rotor blades."
and we say I is correct, II is incorrect which, given the options, I still think is correct. Again if you look at the explanation we see the suggestion that those that wrote the question believe the NGVs to be slightly convergent which will lead to a slight acceleration and a slight pressure drop. This would explain the answer which does not agree precisely with the Rolls Royce book.
210757 is similar, the explanation is similar.
210590 is:
"Regarding a jet engine:
I. The maximum thrust decreases as the pressure altitude increases.
II. The specific fuel consumption is inversely proportional to pressure altitude, at constant TAS."
'slightly' is not an option, but we would agree, and we say exactly that in the explanation. Never the less if PA increases by 60 units and SFC decreases by 1 unit it still is inversely proportional and so the answer "I is correct, II is correct" is true.
Unlawful interference is A7500, not 7700. From PANS-OPS "If there is unlawful interference with an aircraft in flight, the pilot-in-command shall attempt to set the transponder to Mode A Code 7500 in order to indicate the situation. If circumstances so warrant, Code 7700 should be used instead."
You should ask your training provider for their explanation. Who are they?
I cannot say what EASA/the CAA consider to be correct today, we only know what was said when these questions were queried in the past. We have no real-time feed!