Which space exploration activity has most helped astronomers determine the age of the moon? A. Collection of lunar rock samples

B. Experiments performed on the international Space Station

C. Placement of mirrors on the lunar surface

D. Collection of deep space images by the Hubble telescope

Barry is applying the principles of relative dating to a building that has been constructed. analyzing a section of the building, barry says that the lowest part of the section must have been constructed the parts above it were constructed. he bases this conclusion on the principle of . also, looking at a crack forming in the building wall, he says that the crack must be the wall. barry used the principle of to arrive at this conclusion.