What sphere of earth are we ? hydrosphere atmosphere lithosphere biosphere

[ou.01jthe greatest speed with which any physical object moves is 300,000 km/soundsec. which of the following has a speed of 300,000 km/sec? a. light in water b. light in vacuum c. sound in air. d. sound in water

Which outcome is not caused by gravitational forcea. gas and dust come together to form a planet b. planets orbit a star c. two atoms come together to form a molecule d. stars cluster to form a galaxy

Choose the correct chronological or of the time periods