Difficulty is defined by (a) frequency of use, (b) frequency of spelling pattern, and (c) developmental norms. It is not difficult, then, for teachers to place students with words of appropriate difficulty based on simple measures of instructional level (Schlagal, 1996).
If one assumes that shifts in the supply curve of ethanol are solely due to the changing price of corn, then, up to an ethanol price of $2.90, the price of corn completely determines the price of ethanol. In other words, the price of corn drives the price of ethanol, not the other way around. This is actually quite logical since the amount of ethanol used is essentially fixed; consequently, something else must be driving the price of ethanol.
You can produce your own ethanol for an ongoing cost of less than $2 per gallon. If you grow your own corn, you can distill more than 300 gallons of ethanol from 1 acre of corn. If you drive less than 10,000 miles per year, you could produce all your own fuel from 2 acres of corn â and, granted, a lot of labor.