What protected egypt from an invasion?

The Egyptians were protected from invaders due to their geographical features.

Explanation:

They had the Mediterranean Sea to the north along with the Nile Delta. This body of water blocks off land on the other side. Furthermore, the cataracts in the Nile to the south protected the Egyptians from lands below them.

the causes of the dust bowls were severe droughts,   lands became dry and hard, temperature was higher than usual, hot and dry conditions killed crops, high winds. because of those factors, the winds kicked up dry soil and created clouds of dust.