Help me with these questions! (SAT Writing)
1. (When Marie Curie shared) the 1903 Nobel Prize for Physics (with two other) scientists-her husband Pierre Curie and Henri Becquerel-she (had been) the first woman (to win) the prize. (No error).
I chose no error. The right answer was 'had been'. WHY?
2. Most of the sediments and nutrients of the Mississippi River (no longer) reach the coastal wetlands, a phenomenon that has (adversely) (affected) (the region's) ecological balance. No error.
I chose 'the region's'. Isn't 'region's' supposed to be the same as 'region is'? There was no error in this one -.-