Some parts of a sentence have been jumbled up, and labelled P, Q, R and S. Select the option that gives the correct sequence in which these parts can be rearranged to form a meaningful and grammatically correct sentence.

Many psychological, neurological 

P. and different thinking skills that make them leaders rather than followers

Q. studies generally indicate that leaders truly are born with different personality traits

R. to discover if leadership truly can be a learned trait, and

S. and sociological tests have been conducted by scientists