Final answer:
The correct statements regarding the early history of Earth's atmosphere and life are that Earth had a reducing atmosphere and oceans formed shortly after its formation. The atmosphere was not initially composed of oxygen, and the first life forms were not complex multicellular organisms but simple anaerobic ones. The correct answers are options B, C and D.
Step-by-step explanation:
Based on what we know about the early history of Earth, here are the correct statements from the list provided:
b) Oceans formed shortly after the planet's formation: As Earth cooled, water vapor released by volcanoes condensed and fell as rain, filling basins and forming the early oceans.
c) Early Earth had a reducing atmosphere: The first atmosphere was formed from gases like ammonia, methane, water vapor, and carbon dioxide with little to no oxygen present. This reducing atmosphere aided in the formation of complex organic molecules that eventually led to the origin of life.
d) The first life forms were complex multicellular organisms: This is not correct; the first life forms were simple anaerobic organisms, which later evolved into more complex forms.
The incorrect statement is:
a) Earth's atmosphere was initially composed of oxygen: The original atmosphere lacked oxygen and was composed of other gases such as methane and ammonia.