Answer:
"full complement of staff was required"
Explanation:
"The workers of Ellis Island states that a full complement of staff was required to process thousands of immigrants a year."
In the above sentence, we can see that the staffs of Ellis Island are asking for an increase in the staffs working there. The passage "full complement of staff was required" is a clear indication or proof that shows or adds to the central idea of the need for a major workforce increment.
