13. The shortage of a product of resource is called   -- STEM

	a) mass consumption
	b) planned obsolescence     }DISTRACTORS
	c) materialism               ALTERNATIVE
	*d) scarcity                     KEY

* keyed answer

I don't like the term "distractors" because it suggests you are attempting to trick the student, which is not really the idea

- we're adults, they're kids, it's not that hard to trick'em....


-- but we're stuck with the term from long usage, so "distractors" it is