A que se debe que en los bordes de las fallas de las placas tectónicas surjan volcanes?

Which statements are accurate about snow flakes

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.

What is the thickest layer of earth called?