What geographic obstacles made it difficult building the transcontinental railroad

The diagram shows the positions of the sun, moon and earth during spring tides, when the high tides are at their highest and low tides at their lowest. what is it about these positions that causes these high and low tides?

The percentage of people in the united states engaged in agriculture in 2000 was approximately a. 56% b. 38% c. 21% d. 2%

What can happen to solar radiation when it enters earth’s atmosphere? check all that apply. it is absorbed by earth. it is reflected by clouds. it is reflected by glacial ice. it is condensed into visible light. it is amplified by water molecules.