1.5 billion-year-old Earth was all water, no continents

What does the research published in Nature suggest about Earth's condition 1.5 billion years ago?

• The planet was a desert.

• The planet was covered by ice.

• The planet was covered by a vast ocean with no continents.

• The planet had multiple continents.

Where were the ancient sea floor samples, used in the research, located?

• In the Arctic Circle

• In the Outback of northwestern Australia

• In the Amazon Rainforest

• In the Sahara Desert

What significant feature does the ancient sea floor in Australia preserve?

• A fossilized forest

• A volcanic eruption site

• A meteor impact crater

• A hydrothermal system dating back 3.2 billion years

What does the abundance of isotope oxygen 18 in ancient samples indicate?

• A frozen planet

• A planet with dense forests

• A water world without continents

• A dry and arid climate

How did the continents eventually form according to the study?

• Through volcanic eruptions

• By meteor impacts

• Due to plate tectonics pushing land masses upward

• By gradual erosion of ocean floors