Concentration Definition. In chemistry, concentration refers to the amount of a substance per defined space. Another definition is that concentration is the ratio of solute in a solution to either solvent or total solution. Concentration usually is expressed in terms of mass per unit volume.
Answer:
we have lots of bikes and i think that we could improve them to be portable scooters. we also have buses and i think that we should change them to subways to prevent all the pollution. Also i think cars should be less polluted in the future
Explanation: hope this is an okay answer.
D. An electron may acr with either particle like or wave like