Which needle has the smallest diameter?

Smog is the term used to describe the combination of fog and smoke

The characteristic of two different types of reactions are shown below. reaction a: electrons are gained by the atoms of an element. reaction b: protons are lost by the atom of and element. which statement is true about the atoms of the elements that participate in the two reactions? a: their identity changes in both reaction a and b. b: their identity changes in reaction a but not b. c: their identity changes in reaction b but not a. d: their identity remains the same.

About 3% of the water on earth is freshest. only about 40% of that freshwater is available for human use. why is so much freshwater unavailable for human use?