- ESS2-3

Question

Two-Part Question
Part A
Multiple Choice Question
Which claim made in the text is about the ages of rocks?
A.
The oldest ocean floor was formed about the ages of rocks.
B.
A large supercontinent began to split apart about 200 million years ago.
C.
Photosynthesizing organisms appeared about 2.7 billion years ago.
D.
The first oxygen-rich atmosphere developed about 2 billion years ago.
Part B
Multiple Select Question
How does the theory of plate tectonics explain this claim?
A.
Oxygen built up in the atmosphere only after banded iron formations were deposited on the separating continental cratons.
B.
As new ocean floor forms between separating land masses, older ocean floor consumed in oceanic trenches.
C.
The process of new ocean floor formation at ocean ridges began long before the breakup of the supercontinent; different continents and ocean basins existed before Pangea.
D.
Cratons on every continent have evidence of early photosynthetic organisms, since cratons are the oldest crust and have not been involved in tectonic processes.

Answer 1

Part A
The claim made in the text about the ages of rocks is:
B. A large supercontinent began to split apart about 200 million years ago.

Part B
How does the theory of plate tectonics explain this claim? The correct answers are:
B. As new ocean floor forms between separating land masses, older ocean floor is consumed in oceanic trenches.
C. The process of new ocean floor formation at ocean ridges began long before the breakup of the supercontinent; different continents and ocean basins existed before Pangea.