Why is it useful for historians to basbacertain

What was the turning point for the soviets allowing them to regain power and turn back the germans?

As the coach of the u.s. olympic cycling team, i can state without question that the swedish and french teams were using illegal steroids. how else could they have beaten us so badly in the last competition? the u.s. team trained much harder and was much more skilled than our opponents. we only lost because a few teams cheated.

How did german physicist werner heisenberg's uncertainty principle shake beliefs in newtonian physics?