a. are not found in acetyl-coa
b. are formed between sulfhydryl groups and aldehyde groups
c. have resonance stabilization, but much less than oxygen esters
d. have positive standard free energies of hydrolysis

14 days is the half-life of phosphorus-32

answer: atomic mass was originally used to arrange elements on the periodic table, but is no longer used to organize the modern version.

explanation:

originally atomic mass was used to arrange elements on the periodic table from left to right in a row. each column then shows similar properties of elements of a group.

in modern periodic table, the atoms are arranged in increasing atomic number. as atomic number represents the number of protons in an atom which is unique for every atom.