assuming biological substances are 98% water, estimate the masses of a cell with a diameter of 1.1 µm, a human kidney, and a fly. Take a kidney to be roughly a sphere with a radius of 4.2 cm and a fly to be roughly a cylinder 3.3 mm long and 1.0 mm in diameter.

a cell has a mass of how many kg
a human kidney has a mass of how many kg
a fly has a mass of how many kg