What is one advantage using isochrons with Pb/Pb ratios instead of just picking one of the U-Pb systems?

Identify a strong intermolecular force of attraction between an alcohol

Aconcentrated solution of ammonia is 14.8m and has a density of 0.899g/l. what is the concentration of ammonia in this solution in weight percent (%w/w)?

How can carbon move from "land" to bodies of water? describe the way human impact has lead to increased levels of co2 in the atmosphere.