Use a comma to separate items in a series. Although placing a final comma before the coordinating conjunction is often considered optional, omitting it can sometimes cause confusion. Consequently, most scientific and technical writing routinely uses a final comma in a series to prevent possible ambiguities.
His intellectual acuity, diverse
interests, frail physique, and ethereal
personality made Oppenheimer a man of legendary proportions. [In this sentence,
omitting the final comma would not cause confusion. Still, it is good practice in scientific and
technical writing to always include the final comma in a series.]
Contemporary physics is still exploring neutron stars, black holes
and the penetration of electrons through potential barriers.
[The omission of the final comma before and causes ambiguity: are black holes and the
penetration of electrons through potential barriers specific topics connected to the general
subject of neutron stars, or are they separate items?]
Contemporary physics is still exploring neutron stars, black holes,
and the penetration of electrons through potential barriers.
