The Oxford comma

[hubag bohol]

In English punctuation, a serial comma or series comma (also called Oxford comma) is a comma placed immediately before the coordinating conjunction (usually and, or, or nor) in a series of three or more terms. For example, a list of three countries might be punctuated either as "France, Italy, and Spain" (with the serial comma), or as "France, Italy and Spain" (without the serial comma). --Wiki