Which characteristics describe ancient sumerian civilization? select all that apply. a.) social hierarchies b.) city-states ruled by kings c.) monotheistic religion d.) use of terraced fields e.) job specialization

What important discovery was made by edmond halley and alexis clairaut, using newton's ideas of mathematics and gravity? they created the scientific method to outline how science should be conducted. they were able to find the orbit of a comet and predict the year of its return. they discovered the three newest planets--uranus, neptune, and pluto. they explained why objects appear to have color.