Based on the age of the light- and dark-colored regions of the Moon and the number of craters observed in these regions,we know that impacts in the inner Solar System:
A) rapidly decreased approximately 3 billion years ago.
B) rapidly decreased approximately 1 billion years ago.
C) were very rare in the past 4.5 billion years.
D) occurred at approximately a constant rate throughout most of the age of the Solar System.

Question

Quizplus · Accepted Answer

The age of the light- and dark-colored regions of the Moon, along with the density of craters observed in these areas, indicates that the rate of impacts in the inner Solar System decreased significantly around 3 billion years ago. The lighter areas, known as the lunar highlands, are heavily cratered and represent the Moon's oldest surfaces. The darker areas, known as maria, are less cratered, indicating fewer impacts and are formed from volcanic activity that occurred after the period of heavy bombardment. This evidence supports the conclusion that the rate of impacts was much higher in the past and decreased around 3 billion years ago.

Based on the Age of the Light- and Dark-Colored Regions