What causes the alternating pattern of night and day?

Explore the ways that boundaries influence identity, interaction and exchange. things to consider: what is the race/ethnicity. how easy is it to interact/trade with others.

Which was not a country that massively built up its navy in the early 1900s? germany china united statesbritain

According to speculation and study, what will happen to the global birth rate in about 40 years? (1 point)