How was early Earth from more than three billion years ago different from today's Earth? Unlike Earth today, early Earth ________.
A) had an atmosphere rich in gases released from volcanic eruptions
B) had an oxidizing atmosphere
C) experienced little high-energy radiation from the sun
D) had an atmosphere with significant quantities of ozone

Question

Quizplus · Accepted Answer

The early Earth had an active volcanic activity that released gases like carbon dioxide, nitrogen, sulfur dioxide, and water vapor that formed the atmosphere.

Answer: B
 The early Earth had a reducing atmosphere with little oxygen, which is opposite to the oxidizing atmosphere of today.

Answer: C
 The early Earth was not protected by an ozone layer and received more high-energy radiation from the sun.

Answer: D
 The early Earth did not have significant quantities of ozone, as the first photosynthetic organisms had not yet evolved to produce oxygen.

How Was Early Earth from More Than Three Billion Years