About 3% of the water on earth is freshwater. only about 40% of that freshwater is available for human use. why is so much freshwater unavailable for human use? a) it is frozen. b) it is polluted. eliminate c) it is salt water. d) it is in aquifers.

State one advantage and one disadvantage of using a plane mirrior as a driving mirrior

Asubmarine has a "crush depth" (that is, the depth at which water pressure will crush the submarine) of 250 m. what is the approximate pressure (water plus atmospheric) at this depth? (recall that the density of seawater is 1025 kg/m3, g = 9.81 m/s2, and 1 kg/(ms2) = 1 pa = 9.8692 10-6 atm.) a. 34.8 atm b. 24.8 atm c. 25.8 atm d. 7.8 atm

Frequency of electromagnetic waves that a radio station is assigned is called