Why was egypt called a river civilization?

The blank theory suggests that the sun, planets, and other celestial bodies of the solar system came from a cloud of dust and gas? a.) condensationb.) steady state c.) big bang d.) nebular

According to the united nations refugee agency, more than 2/3 of the world's refugees come from just five countries. which country is not on that list? a) turkey b) myanmar c) afghanistan d) south sudan

One of the brightest comets of the 20th century was comet hyakutake, which passed close to the sun in early 1996. the orbital period of this comet is estimated to be about 30,000 years. find the semi-major axis of this comet’s orbit. compare it to the average sun-pluto distance and to the distance to alpha centauri, the nearest star to the sun, which is 4.3 light-years distant.