Did you type this out? lol
Seismograph's drum feel the seismic waves. There is a weight that moves the pen so that when the seismic waves are felt, the pen jiggles and records it on paper.
<u>Answer:</u>
Ptolemy accounted for 'retrograde motion' in his model of the solar system by introducing smaller circles named 'epicycles'.
<u>Explanation:</u>
- According to Ptolemy, the Sun and the other planets in the Solar system orbited around the Earth.
- The Greeks were convinced that Ptolemy's earlier model did not provide for backward or the retrograde motion.
- Ptolemy thought over it for a while and theorized the possibility of 'epicycles'.
- According to Ptolemy, the planets that orbited Earth also orbited another smaller point.
- The smaller orbits followed by the planets while in motion around the Earth in a larger orbit were introduced by Ptolemy as 'epicycles'.
- Until Kepler proposed his models of the functioning of the Solar system, Ptolemy's models were considered the most relevant.
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It is important for the United States to build canals (wide canals) because the country is visited multiple times by hurricanes annually. Hurricanes are accompanied by heavy rainfalls and if left unchecked, causes flooding. The function of canals is to diffuse accumulated rainwater and direct it to greater bodies of water.
Using the principles of cross-cutting relationships, you can determine the relative age of rocks found in the ground. The idea behind it is that the geologic feature which cuts another is the younger of the two features, and it had been around for 400 years. It's not very precise but it is good for determining relative age.