When Mary earned $3,200 per month, she bought 2 concert tickets each month. Now her monthly income is $5,600, and the number of concert tickets she purchases has risen to 3 per month. Mary's income elasticity of demand for concert tickets equals ________ and the tickets are a(n) ________ good for Mary.

An indifference curve:

A) may be either upsloping or downsloping, depending on whether the two products are complements or substitutes. B) is downsloping and convex to the origin. C) is upsloping and has a constant slope. D) is downsloping and concave to the origin.

Which of the following statements is true?

a. An opportunity cost is what must be given up in order to get something else. b. The three fundamental economic questions refer to What to produce? How to produce? and When to produce? c. The term "investment" refers to the purchase of stocks and bonds and other financial securities. d. The law of increasing opportunity cost implies that as production of one type of good is expanded then fewer and fewer of other goods must be given up.