Which of the following statements concerning the three-field rotation system is most accurate?
a. The three-field system removed fallow fields and replaced them with nitrogen-bearing crops.
b. The three-field system was rapidly replaced after the 8th century by the two-field system that offered greater flexibility in terms of crop rotation.
c. It represented a net increase in productivity where it was used because although crops were rotated, no fields were left fallow.
d. The three-field system removed more land from production than before by reserving one-third for fallow.
e. Introduced in the 8th century, the three-field rotation left a third of the land unplanted to regain fertility.
Answer: E