Among dogs, cats, and primates, which group had the highest usage in the United States during the period described?

• A. Dogs
• B. Cats
• C. Primates
• D. Rabbits

Answer: (A)

The main idea being tested is how usage of different animal groups compares within U.S. research during the specified period. The data show dogs were used more frequently than cats or non-human primates in that timeframe. This reflects historical patterns where dogs have been widely employed in pharmacology and toxicology studies because their physiology can provide relevant insights for human safety, and there are established testing protocols and regulatory familiarity. Cats are used in certain niche areas but overall not as common, while primates require especially stringent ethical justification, higher costs, and tighter regulation, which keeps their numbers comparatively low. So, among the three groups, dogs have the highest usage in the United States for that period.