Answer:
North Africa is mostly desert. But the ancient Egyptians found that they could grow crops by irrigation ditches from the Nile River
Explanation:
C
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Answer: the four terrestrial planets must once have been hot enough to be molten (like a liquid)
Explanation: Terrestrial planets can be defined as any planet of the solar system or any exoplanet which is "Earth-like" in the sense that it is composed primarily of metals and rock, in contrast to a planet which is a gas giant.
Within the Solar System, the terrestrial planets are the inner planets closest to the Sun, i.e. Mercury, Venus, Earth, and Mars.
Scientist believing that the densest, heaviest materials are at the center and not evenly distributed can be due to the fact that they must once have been hot enough to be molten. In this case, density will take place, making the heavier under and the lighter on top.