Question:
The airline unions constantly go on strike against the airlines because they want better salaries.

they
Answer:
The airline unions
Question:
The squirrels buried the nuts so they would not lose them.

they
Answer:
The squirrels
Question:
Peter Griffin often pokes fun at Chris, so he always ends up being angry.

he
Answer:
Chris
Question:
Animal Control takes control of lost animals in the city because they are hired by the city to perform these duties.

they
Answer:
Animal Control