Not sure what your question means but the nearest star is Alpha Centauri which is about 4.2 light years (ly) away. This is roughly 4x10¹³ km away. A billion is 10⁹ so this is 4x10⁴ larger than a billion. I'd say the last one then...
True. Though typically crack deals take place in a car, or in an alley. The middle of a long block is kind of exposed. It could happen anywhere in Chicago though. But yeah, criminals structure crime.
The control setup in this experiment would be one tank that does not contain any of the additives. Since the tanks with the gasoline additives would need to be compared with a tank that is not affected by the results of these additives.
