The axis of Earthâ€™s daily rotation is tilted with respect
to the plane of its orbit at an angle of roughly 23
degrees. That angle can be kept fairly stable only by
the gravitational influence of Earthâ€™s large, nearby
Moon. Without such a stable and moderate axis tilt, a
planetâ€™s climate is too extreme and unstable to
support life. Mars, for example, has only very small
moons, tilts at wildly fluctuating angles, and cannot
If the statements above are true, which one of the
following must also be true on the basis of them?
(A) If Mars had a sufficiently large nearby moon,
Mars would be able to support life.
(B) If Earthâ€™s Moon were to leave Earthâ€™s orbit
Earthâ€™s climate would be unable to support
(C) Any planet with a stable, moderate axis tilt can
(D) Gravitational influences other than moons have
little or no effect on the magnitude of the tilt
angle of either Earthâ€™s or Marsâ€™s axis.
(E) No planet that has more than one moon can
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