PREP1-36，并列的问题

1.           Thomas Eakins's powerful style and his choices of subject--the advances in modern surgery, the discipline of sport, the strains of individuals in tension with society or even with themselves-- were as disturbing to his own time as they are compelling for ours.

我标红的部分，我认为是三个并列，做同位语解释choices of subject

既然是并列，为什么能不用xx, xx and xx这种结构？请高人指点