The SRAS curve is vertical at the natural level of real output

The ceteris paribus assumption means

A) favors are returned in kind. B) this is the proof of the matter. C) from many, one. D) other things are equal.

(Refer to the figure provided in the text.) For the share of income spent on food to remain constant as income rises, the Engel curve must

a. lie above the 45-degree line. b. lie below the 45-degree line. c. be equal to the 45-degree line. d. bisect the 45-degree line.