What occurred during the Middle Kingdom? A: the construction of pyramids
B: The introduction of a writing system
C: the development of religious beliefs
D: the formation of a strong central government

These factors threaten north americas ecosystems

If we represent the solar system on a scale that allows us to walk from the sun to pluto in a few minutes, then a) the planets are microscopic and the stars are millions of miles away. b) the planets are the size of basketballs and the nearest stars are a few miles away. c) the planets are marble size or smaller and the nearest stars are thousands of miles away.

Which season has the least amount of rain in the northern latitudes