The Nile River provided the Ancient Egyptians with fertile land to grow crops since most of Egypt is desert. They also sold a lot of their wheat throughout the Middle East making the Egyptians rich.
An atlas is a primary source.
I believe the answer is: <span>motion aftereffects
</span><span>motion aftereffects refers to a visual illusions that make a non-moving stimulus appear to no move in opposite direction.
Motion aftereffects is commonly caused when we fixated on a moving objects with a stationary eyes for a long period of time.</span>
