Describe the changes that occur inside a helium balloon as it rises from sea level

The balloon expands in the number of particles per cubic centimeter decreases. This happens because as it expands there is a decrease in the density of area. The Dead Sea is a solution that is so dense that you easily float on it.

e) none of the above answers are correct

electric field is a function of 1/r^2

yes, the force per unit charge for a point charge is inverse square law.