Respuesta :
Immigrants contribute to unemployment among native-born workers.
The correct answer is:
Immigrants contribute to unemployment among native-born workers.
This was and even nowadays is a common case, because normally people who immigrate are from the third world countries (in the majority of cases) and they are ready to go to any work, even if it is physically hard. In such way, they leave very little choice to the native-born workers or even take options available for them.