Good one.
Isolate
parallelism- suppliers are growing ........, ing , ing.
showing sub suppliers doing something to increase production.
now see what their refers to, sounds like it refers to the supplier not the fish. They makes it sound better and easier to see that 'they'points to the fish and not the supplier.
hope this helps.
Khurram
GMAT Prep
This topic has expert replies
Source: Beat The GMAT — Sentence Correction |

















