The main purpose of the comma is to group words that belong together and separate words that do not.?

A new synthetic narcotic has been developed by the pharmaceutical industry. This drug, called Drug A, has three times the efficacy of an existing synthetic narcotic, Drug B. However, Drug B has twice the affinity for opiate receptor sites in the body as Drug A. Which drug will have the greater effect when administered at the same dosage?

A) Drug A B) Drug B C) Identical effects when administered at the same dosage D) Cannot be determined by the information given

Reticulocytes generally mature within ________.

A. 36 hours B. 48 hours C. one week D. one month