Scientists classify rocks into three different types. what is the main basis for the classification system they chose? a. color of the rock b. shape of the rock c. how the rock formed d. who discovered the rock

Why does less erosion & more deposition take place on the outside bank of a meander?

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.