QUES:
Who is he in the following sentence?

Caesar the ape found out the door code by watching Morris, because he was careless when typing in the code.

ANS:
Morris

QUES:
Who is he in the following sentence?

Beowulf was granted the crown to succeed King Henry because he did not have a son to secede him instead.

ANS:
King Henry

QUES:
Who is they in the following sentence?

Hybrid cars produce less pollution than diesel trucks because they use pure gasoline.

ANS:
diesel trucks