According to ptolemy's model of the movement of celestial bodies, a. the sun is the center of the universe. b. the earth rotates around the sun. c. planets orbit in circular paths around the earth. d. the earth rotates around the moon.

Silica, sio2, is formed on silicon as an electrically insulating layer for microelectronic devices. silica is formed when silicon is exposed to o2 gas at an elevated temperature. at 900˚c, it takes 90 minutes for the oxygen to diffuse from the surface to form a 0.06 micron (0.06 x 10-6 m) thick layer of sio2 on

An empty fuel tank can still contain and therefore can be even more dangerous than one full of liquid fuel.

How many grams of mgbr2 are needed to produce 75g or metal?