NASA’s Cassini probe has detected an unusual wobble in the rotation of Mimas, Saturn’s smallest moon. Using a computer model to study Mimas’s gravitational interactions with Saturn and tidal forces, geophysicist Alyssa Rhoden and colleagues have proposed that this wobble could be due to a liquid ocean moving beneath the moon’s icy surface. The researchers believe other moons should be examined to see if they too might have oceans hidden beneath their surfaces.

Question

Which choice best states the main idea of the text?
Choose 1 answer:
Choose 1 answer:
(Choice A) Rhoden and colleagues were the first to confirm that several of Saturn’s moons contain hidden oceans.
A
Rhoden and colleagues were the first to confirm that several of Saturn’s moons contain hidden oceans.
(Choice B) Research has failed to identify signs that there is an ocean hidden beneath the surface of Mimas.
B
Research has failed to identify signs that there is an ocean hidden beneath the surface of Mimas.
(Choice C) Rhoden and colleagues created a new computer model that identifies moons with hidden oceans without needing to analyze the moons’ rotation.
C
Rhoden and colleagues created a new computer model that identifies moons with hidden oceans without needing to analyze the moons’ rotation.
(Choice D) Research has revealed that an oddity in the rotation of Mimas could be explained by an ocean hidden beneath its surface.
D
Research has revealed that an oddity in the rotation of Mimas could be explained by an ocean hidden beneath its surface.

Answer 1

The best choice that states the main idea of the text is:

(Choice D) Research has revealed that an oddity in the rotation of Mimas could be explained by an ocean hidden beneath its surface.

This choice accurately reflects the focus of the text on the detected wobble in Mimas's rotation and the hypothesis that it could be due to a liquid ocean beneath the surface.