How many ml of 0.4 m solution can be made from 1200 ml of 2.5m solution

This drawing shows a human body system. what is the primary function of this body system?

At 450 mm hg a gas has a volume of 760 l, what is its volume at standard pressure

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?