Complex sentence: Normal fear of heights, as opposed to acrophobia, reduces as one gets used to it, and so one can be "trained", in that sense, to acquire a head for heights, independent of one's biological disposition.
Split into simpler sentences: Normal fear of heights, as opposed to acrophobia, reduces as one gets used to it. One can be "trained", in that sense, to acquire a head for heights, independent of one's biological disposition.