Final answer:
The scratch plow was improved around 600 AD with the addition of a metal blade and wheels, facilitating better soil cultivation and advancing agricultural techniques. The correct option is A.
Step-by-step explanation:
The improvement of the scratch plow around 600 AD included the addition of two major parts, specifically a metal blade and wheels. These advancements significantly enhanced the efficiency of plowing, enabling farmers to cultivate heavier soils more effectively.
The integration of a metal blade allowed the plow to cut through soil with greater ease, while the incorporation of wheels helped in the easier movement and control of the plow.
This technological progress was a stepping stone in agricultural development, which subsequently led to increased crop productivity and the growth of settled farming communities, thanks to a reliable food supply.
Historical innovations such as the heavy plow and the three-field rotation system further advanced agriculture beyond the capabilities of the original scratch plow. Such innovations were pivotal in shaping the agricultural practices of the time, allowing for increased efficiency in food production.