QUES:
Who is they in the following sentence?

The Magnificent Five will battle it out with Shen Yu's forces, but they may try and run away.

ANS:
Shen Yu's forces

QUES:
Who is it in the following sentence?

The food in the refrigerator went bad because it was past the expiration date.

ANS:
The food

QUES:
Who is they in the following sentence?

The officers chose a planet to send the new soldiers so they could receive experience in hostile environments.

ANS:
the new soldiers