Is it true that the struggle between organisms to survive in a habitat with limited resources called natural selection

Which describes radioactive decay of a substance

Could someone me with number one you

Most of the fossils found in virginia are in the coastal plain, valley, ridge, and appalachian plateau regions, best suggesting that these geographic provinces a) were once covered by seawater. b) are the oldest parts of virginia. c) have a great deal of karst topography. d) have large amounts of sedimentary rock.