Although magma once filled our moon's craters, what is thought to have ended there over a billion years ago?
deserts activity
mineral activity
oceanic activity
volcanic activity
When you look at the Moon from Earth, you notice dark and light areas. The maria are dark, solid, flat areas of lava (mostly basalt). Maria covers around 16% of the Moon’s surface, mostly on the near side. The maria formed about 3.0 to 4.0 billion years ago, when the Moon was continually bombarded by meteoroids ( Figure below ). Large meteorites broke through the Moon’s newly formed surface. This eventually caused magma to flow out and fill the craters. Scientists estimate volcanic activity on the Moon ended about 1.2 billion years ago.