Variations in the shape of the earth's orbit:
A)have a cycle of about three million years.
B)have a cycle of about 100,000 years.
C)will eventually lead to the earth having a perfectly circular orbit.
D)are related to changes in sunspot activity on the surface of the Sun.

Question

Quizplus · Accepted Answer

The shape of the earth's orbit varies in a cycle of about 100,000 years. This is known as the Milankovitch cycle, which includes variations in eccentricity, axial tilt, and precession of the equinoxes. This cycle is believed to be responsible for the alternating periods of glaciation and warming on earth. The other choices are incorrect; A is too long a cycle, C is unlikely to happen, and D is not related to the shape of the earth's orbit.

Variations in the Shape of the Earth's Orbit