<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.
Answer: D
Explanation:
They are trying to adapt to the resources around them.
Answer:
Fast
Explanation:
For a river that deposits small particles where it flows into a sea, the current is likely to be fast.
A fast current is only able to winnow through the sediment and removes the fines.
- On reaching the river mouth with the sea, they settle and get deposited
- For a slow current, there is enough time for the energy to get along with the sediments.
- This ensures the proper drag of the particles throughout the session into a basin or the river mouth.
- Most fast currents are not usually deep enough to remove the coarse particles.
