How do impact craters reveal a surface’s geological age? ?

According to the population pyramid, in 2000 china had about 120 million people in which age-group

According to the marxist theory which of the following people would be member of the proletariat

After examining the evidence at a site, a geologist thinks that a river could have once flowed through the area. what evidence would support this conclusion? a) the site is a vast, open grassland. b) a high level of tectonic activity is present. c) this location contains igneous rocks everywhere. d) many sedimentary rocks with fossils have been found.