Most scientists agree that life began on earth approximately 3.5 billion years ago. What would a scientist need to do in order to test this hypothesis and gather evidence?
A: Recreate the composition of the atmosphere and oceans on Earth as they were 4.5 billion years ago.
B: Travel to a similar planet or moon in its own early formation and recreate the chemical reactions which took place on Earth.
C: Gather the raw materials, such as inorganic compounds, on Earth 4.5 billion years ago and recreate the chemical reactions that could have taken place.
D: This is not a testable hypothesis since there is no way to travel back 4.5 billion years or to run the experiment for the next 4.5 billion years.
Today, the atmosphere holds about 21 per cent oxygen. ... When the first simple organisms appeared in the oceans more than 3.5 billion years ago, the atmosphere was mostly nitrogen, hydrogen, water vapor, and carbon dioxide
