If the two balls are hanged near one another without touch or an external charge to any of the balls there would be no charge present. In the given question is it given that two balls hang down without any contact in them.
So there is no possible way to generate charge and remain uncharge in their position till they get any external charge.
There is safety in numbers, and with that, they can run together more often without the fear of being attacked, and must push themselves to match others, therefor getting fit
