Which two elements are found in significant amounts (1% or more) in both the Universe and the human body?

the ratio of the conjugate base to the acid required to attain the desired ph.

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.