You haven't completed the exercise.
1a. Which words does the speaker stress?
start / water / history
start / where / comes / history
1b. Which words does the speaker stress?
first / make / Earth / all / ever
first / make / water
1c. Which words does the speaker stress?
accepted / theory / created / formed / reaction / hydrogen / oxygen
scientific / first / formed / reaction / hydrogen /oxygen
1d. Which words does the speaker stress?
dropped / water / downpour / 60,000 years
dropped / layer of cloud / torrential downpour / amazing / 60,000 years
1e. Which words does the speaker stress?
remarkable / level / the oceans / the amount / the Earth / remained / stable
thing / the oceans / water / remained / stable / since