Farmers in a certain region have noticed a decrease in the variety of crops that they are able to successfully grow in the region. This has impacted the number of crops that they are able to sell to consumers. Which of the following changes has most likely caused this change in biodiversity? A. increased soil aeration caused by an increase in earthworms B. increased soil fertility caused by an increase in animal waste C. increased space availability caused by an increase in average field size D. increased acid rain caused by an increase in pollution