The present quantity of water on Earth was achieved approximately ________ years before the present.
A)one million years ago
B)500 million years ago
C)two billion years ago
D)10 000 years ago (end of ice age)
E)4)6 billion years ago

Question

Quizplus · Accepted Answer

The present quantity of water on Earth was achieved approximately two billion years before the present, during a period known as the "Great Oxidation Event" when photosynthetic organisms released oxygen into the atmosphere, leading to the formation of ozone and the protection of the planet from ultraviolet radiation, allowing water to accumulate on the surface. Option A is too recent, option B is too early, option D is related to a specific event (end of ice age) but not the overall quantity of water, and option E is the age of the Earth, not specifically related to the water quantity.

The Present Quantity of Water on Earth Was Achieved Approximately