Explain why the soil on Sandoval’s farm is "less vulnerable to erosion" than soils on neighboring farms. Identify two characteristics of Downer soils, focusing on the top two soil horizons, and explain how each characteristic likely makes it difficult to grow crops in Downer soils. Explain how crop rotation and cover crops could help a farmer overcome these difficulties.

The soil materials at Sandoval's farm are comparatively less vulnerable to erosion because there implement the method of crop rotation and the soils are mostly covered with vegetation. So, they are not easily affected by wind, water, as these agents are responsible for the cause of erosion.

The two of the characteristics of Downer soils that makes it difficult to grow crops are as follows-

These Downer soils do not provide the necessary conditions for the crops to grow due to the presence of gravel particles, as it creates difficulty for the plant roots to grow in the subsurface and support the entire plant body.

Crop rotation and crop cover or vegetation cover are two of the possible ways in which the soil fertility is maintained, as during crop rotation, different crops are grown and different minerals are used. So the soil is enriched with varieties of mineral nutrients helping in the growth of crops. It also helps in diminishing the possibilities of soil erosion and improves the drainage pattern.

the answer would be the third option, "no, ariel should have added 9^2 and 12^2 and compared that to 15^2."

this is found through the pythagorean theorem, which is a^2 + b^2 = c^2.

this is the correct way of solving the problem:

9^2 + 12^2 = 15^2

81 + 144 = 225

225 = 225