Why is the rod of an electroscope always made metal?

If it is negatively charged, then excess electrons “run away” into your body, if positively, then the electrons from your body neutralize the shortage, i.e. condenser atoms acquire missing electrons and become neutral.

Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.