Muntari, firstly don't count yourself part of the professional pilot community yet - you've a very long way to go. The most important job on an airliner varies with the circumstances - it may very well be the defibrillator-trained member of cabin crew who is attempting to revive the victim of a heart attack, or those whose job it is to evacuate the aircraft in the event of a crash-landing. When you finally reach the dizzy heights of brand-new second officer, you will need to examine your tea or coffee carefully if you 'dis' your cabin crew....!
As for fitness, the only test you may undergo is a swimming test fully clothed. Not many airlines still do this, but some do.
Scroggs