Why were the Nile cataracts a problem for Kush? Please help

https://www.google.com/search?q=nile+cataracts&oq=nile+cataracts&aqs=chrome..69i57j69i60.4901j0j7&sourceid=chrome&ie=UTF-8
Make absolutely sure you know what the Nile cataracts are and how they can be dangerous for boats.

Also read the articles here:
https://www.google.com/search?ei=iC6yW7iXEtTq9APp3ZXIAg&q=nile+cataracts+hurt+kush&oq=nile+cataracts+hurt+kush&gs_l=psy-ab.3...69713.76047..76468...3.0..0.141.1645.0j13......0....1..gws-wiz.......0j0i71j0i22i30j33i21j33i160.V7wVBUIcIaY

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And thx for the help

what awnser tell me or ill sew you

Ok I'm stumped lol.

Sean sameeee

Their trading boats were unable to go past them.

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