Jehovah's Witnesses, and indeed many christians, believe Jesus Christ is their redeemer.
The Watchtower Society sets forth a specific formula for this doctrine:-
Adam, a pefect man, sinned and lost everlasting life. We inherited his sin, and so we conitnue to pay the price of death.
Jesus, a perfect man, was sinless and in giving his life, gained back our chance at everlasting life. He paid the ransom, and eliminated the need for us to die for our sins.
So, the obvious question arises:-
WHY DO WE STILL DIE? If Jesus has paid the price, if what Adam lost has been restored, if we have truly been redeemed and the ransom price paid (and presented to Jehovah according to the Bible...) then why do we still die? Why are we still living in 'sin' 2,000 years later?
(Curious to see how people who believe this doctrine respond...)