Hey there! I'm happy to help!
The Fertile Crescent is basically where human civilization started. It stretches from Mesopotamia and across the Mediterranean coast to Egypt. Early civilizations depended on agriculture. To make agriculture, you need a river because it is a good water source to help grow your crops.
If you look at the map I have provided below, you will see that there are tons of rivers. This would make it very easy for settlers to grow crops. This means that sea tides and eroding mountains aren't the answer. I don't think the rivers were flooding and natural canals is an oxymoron because canals are artificial waterways, but this all should give you and idea.
Have a wonderful day! :D
Answer:
The answer is that the actual shape of the planetary orbit around the sun is elliptical.
Explanation:
The actual shape of the orbit of a planet around the sun is elliptical.
The assumption made by the Newton regarding the shape of an orbit of a planet around the sun was that the orbit of a planet around the sun is 'circular'.
Hope this helps!! ;)
Laurasia and Gondwanaland, the sea in between these two land masses was called the Tethys sea and this all formed about 200 million years ago.
Tectonic Plates would be the answer