Soybeans and corn are both used as animal feed. (70% of Soybeans are used as animal feed, and Corn is the primary animal feed in the US.) Also, on many farms, farmers can grow either soybeans or corn. Ethanol is a fuel derived from corn. Ceteris parabus: If demand for ethanol fuel increases causing the equilibrium price of corn to increase, what will happen to the market for soybeans