What would the density of a human be

Density is measured by mass and volume. Mass is weight and volume is the amount of space a object has. So depending on the person's mass and volume would determine the density of that person but the average density a person has would be: "985 kg/m^2."

Hope this helps!

if you already have the answer to (a), then just work out how many periods there are in 1 minute, and that's the answer to (c).