Which of these places has a low population density?

In the millikan oil drop experiment they determined that every drop had a charge which was a while number multiple of -1.60x10^-19. if a drop has a total charge of -9.60x10^-19 then how many excess electrons are contained within the drop?

What happened to the amount of carbon dioxide in the atmosphere from 2010–2017?

How many moles of sulfur dioxide are produced when 4.38 moles of oxygen completely react with iron (iv) sulfide