Hieroglyphs, petroglyphs (pictures carved into rocks), and cuneiform (a writing system using hashmarks on clay tablets) were all early forms of written communication. All of them were precursors to alphabets, which use letters to represent sounds. Grunts are an early (and present-day) form of communication, but they aren't written.
Answer:
The world is not flat for it is actually a sphere. This sphere is filled with hot and cold layers that make up the Earth. :)
Explanation:
The answer is communication.
C
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