Difference between phosphorus
and potassium​

Potassium is a mineral found in most of the foods we eat and is necessary in the diet because it helps with muscle movement and keeping the nervous system healthy. ... Phosphorus is also a mineral we get from eating certain foods. Phosphorus helps build strong bones and teeth.

a:

by the combination of an unlimited number of elements

a 20-cm-long, cylindrical graphite (pure carbon) rod is inserted into an oxidizing atmosphere at 1145 k and 1.013 x 105 pa pressure. the oxidizing process is limited by the diffu- sion of oxygen counterflow to the carbon monoxide that is formed on the cylindrical surface.