Answer:
My answers is Mediterranean Sea.
Explanation:
If I need to choose only one answer it would be Mediterranean sea, as it was to the north to Egypt, which meant that it was impossible to attack Egypt from North without navy.
Red Sea can be also the correct answer as it protects Egypt from the east, although Sinai Peninsula connects Egypt with Asia.
Tigris and Euphrates are in Mesopotamia, not Egypt.
Nile is not correct as the river flows across Egypt and couldn't prevent invasion.
Separation of Powers. The division<span> of state and </span>federal government into three <span>independent </span>branches<span>. The first </span>three<span> articles of the </span>U.S.<span> Constitution call for the powers of the </span>federal government<span> to be divided among </span>three<span> separate </span>branches<span>: the legislative, the executive, and the judiciary </span>branch<span>.</span>
