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.
The E10 blendwall not only has profound implications for the implementation of RFS mandates, but also for market price relationships. As long as the E10 blendwall is binding, the price of corn drives the price of ethanol. This is a reversal of the relationship between ethanol and corn prices that has been in place for much of the ethanol boom.