I just need help with these four geographic question they are due at 6:30

Arid and semiarid subcategories are part of which climate

Explain why components that are naturally found in air can be considered air pollutants.

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.