When were most of the existing lava plains formed on the surface of Mercury?
A) Never.There is no evidence of lava flows on the surface of Mercury.
B) When Mercury was first formed,about 4.5 billion years ago
C) At the end of the era of heavy bombardment,about 3.8 billion years ago
D) When the crust wrinkled to form the scarps

Question

Quizplus · Accepted Answer

Most of the existing lava plains on the surface of Mercury were formed at the end of the era of heavy bombardment, about 3.8 billion years ago. This is evidenced by the fact that the lava plains are more extensive on the side of Mercury facing away from the Caloris Basin, which was formed during the early era of heavy bombardment. The lava plains are also younger than many of the impact craters on the surface.

When Were Most of the Existing Lava Plains Formed on the Surface