In the following degrees — "Bachelor of Science" and "Master of Science" — "science" is an uncountable or singular noun. In contrast, in "Bachelor of Arts" and Master of Arts, "arts" is countable and plural. Wikipedia says the Master of Arts "degree is usually contrasted with the Master of Science."

Let's say different regions in a country are divided into two categories - high and low unemployment regions. Low unemployment regions have plenty of job opportunities, but workers in high unemployment regions won't relocate to these low unemployment (and high productivity) regions. This is becau...