The equation for density, d, is d=*
where m is mass and V is volume.
What is the density, d. of a substance with a volume of V = 11.3 cm and a mass of m = 60.4 g ?

a gas, having a molecular weight of 13 kg/kmol and a kinematic viscosity of 0.25 cm2/s, flows through a pipe 0.25 m internal diameter and 5 km long at the rate of 0.4 m3/s and is delivered at atmospheric pressure.

answer: they produce more slow than unicellular organisms.