Why does convection occur in the mantle?

These factors threaten north americas ecosystems

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.

Islam and the arabic language spread throughout north africa in the 600s primarily through a. african traders b. american colonists c. european explorers d. middle eastern armies select the best answer from the choices provided