ConceptChecks
ConceptCheck 10-1: The darker color of the maria comes from solidified iron-rich lava that has partially filled large impact basins. These impact basins are deep (with the South Pole—Aitken Basin reaching depths of 12 km) and partial filling by lava still leaves the maria surfaces at lower elevations.
ConceptCheck 10-2: Figure 10-13 shows conclusive evidence of water on the Moon because the observed spectrum is such a good match to the known spectrum of water. An excess of hydrogen atoms is likely due to water, but is less certain because it could also arise from unusual minerals.
ConceptCheck 10-3: No. The Moon’s liquid iron-rich core is too small for the convection that creates a magnetic dynamo. This is why the Moon today has no global magnetic field.
ConceptCheck 10-4: No. Impacting micrometeorites constantly “weather” the surface of the Moon. After a billion years, this weathering might even erase a 400-meter-wide crater.
ConceptCheck 10-5: Yes. The Moon has a lower average density than Earth, indicating a lower iron fraction. If Earth’s iron sank before the impact, then outer material forming the Moon would be lower in iron.