Development of Earth's early oceans was likely due to
A) water-rich meteors bombarding Earth's surface.
B) volcanic outgassing in Precambrian time.
C) intense convection in the mantle, and severe heat dissipation from Earth's interior.
D) cooler temperatures that promoted the condensation of water vapor in the atmosphere.
Question 2
The banded iron formations began to form when
A) carbon dioxide dissolved in seawater.
B) varying oxygen levels allowed the precipitation of alternating layers of iron oxide.
C) oxide minerals were deposited on the ocean bottom.
D) iron from lava flows settled into layered formations.