Use this fact to answer the question: as the use of a crop increases , the amount of crops planted will increase

A person feeds their cows corn. They grow an acre of corn each year for the herd. They add another thirty cows to their herd, so they

Pick from:
 + burn the corn.
 + grow less corn.
 + plant several acres.
 + remove some cows.

The answer is:
plant several acres