Question

Unless the biodiversity of the sea were maintained, marine life would be at stake

-> If the biodiversity of the sea

Without plants, most water would run off

-> If

Answer 1

Without plants, most water would run off

-> If there weren't any plants, most water would run off​

Answer 2

Unless the biodiversity of the sea were maintained, marine life would be at stake

-> If the biodiversity of the sea weren't maintained, marine life would be at stake

Without plants, most water would run off

-> If there aren't any plants, most water would run off