The timeline shows the history of mapmaking. A timeline. The timeline begins at 15,000 B C E and ends at 2000 C E. 14,000 B C E Natural objects. 200 B C E Greeks. 400 C E Middle Ages. 800 C E Arabic globe. 1100 C E Chinese printed maps. 1973 C E Digital maps.

Gold is not now being extracted from seawater. why not? a. it would be too disruptive to marine life to develop any marine mineral resources b. there is no gold in seawater c. we don't know how to extract minerals from seawater d. it would be too costly and difficult to separate the small amount of gold from the very large amounts of halite and other minerals

The layers of earth are based on what two sets of characteristics?

Some gamma ray bursts are hypothesized to come from mergers of neutron stars or black holes. if this hypothesis is correct, what else should we in principle be able to detect from such mergers? a. gravitiational waves b. x-ray bursts c. significant disruption of gas thousands of light-years away in the surrounding galaxy d. an "afterglow" of bright visible light, lasting for weeks