According to the usda, soil surveys show more than __% of natural topsails in north america has been lost since farming began in the u. s.

30%

Explanation:

Every consecutive year the loss of topsoil becomes a serious issue for the farmer and policymaker. The reason behind the continuous loss of topsoil is when the upper layer of soil left fallow and exposed to heavy rains and winds. which takes the upper surface with them.

The practice like grazing of field and growing of crop on steeper slopes and continuous practice like crop rotation are the main reason behind the soil erosion.

As the country is moving toward the fast technology phase, practice of securing land to prevent it from erosion is lacking. The other reason behind the fast removal of topsoil is the use of modern technology to grow a crop.

because the sun creates the shadows and its only what people on earth see in the sky which are the phases of the moon.