Are hexane and cyclohexane isomers? Why or why not?

No, they are not isomers

Explanation:

"The molecular formula of cyclohexane is C6H12 while of hexane, it is C6H14. The isomers are those molecules which have same molecular formula. Hence on this bases, the above two are not isomers"

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the solute can move "downhill," from regions of higher to lower concentration, relying on the specificity of the protein carrier to pass through the membrane. this process is called passive transport or facilitated diffusion, and does not require energy.