The axis of Earth’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 Earth’s large, nearby
Moon. Without such a stable and moderate axis tilt, a
planet’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
support life.
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 Earth’s Moon were to leave Earth’s orbit
Earth’s climate would be unable to support
life.
(C) Any planet with a stable, moderate axis tilt can
support life.
(D) Gravitational influences other than moons have
little or no effect on the magnitude of the tilt
angle of either Earth’s or Mars’s axis.
(E) No planet that has more than one moon can
support life.
_________________
“If money is your hope for independence you will never have it. The only real security that a man will have in this world is a reserve of knowledge, experience, and ability.â€