Why did Earth form into seperate layers?

Which of the following was a similarity between classical mesoamerican and south american civilizations ?

The internal combustion engine was an innovation of

Read the excerpt from the history of herodotus, book 2. egypt . . is an acquired country, the gift of the river. this quotation from herodotus, a greek who traveled in egypt, is about how the nile river enabled ancient egyptian civilization to develop and succeed. what specifically was the river’s gift? fertile soil fishing stocks defensive capabilities drinking water