Which of the following plants typically generates seeds with the highest protein content?

Soybeans are known for their high protein content, which is a key reason they are widely used in animal feed and as a source of protein for human consumption. The protein content in soybeans generally ranges from 30% to 40% of the seed's weight, making them one of the most protein-dense crops available. This high protein content is due to the biochemical makeup of soybeans, which includes a significant amount of essential amino acids that are crucial for both human and animal nutrition.

In contrast, while hard white wheat and hard red winter wheat do provide some protein, their levels are typically lower, usually around 10% to 15%. Grain sorghum also contains lower protein levels, generally in the range of 9% to 14%. These grains serve different purposes in agricultural systems and are often valued for their carbohydrate content rather than protein. Thus, when considering protein density in seeds, soybeans stand out significantly compared to the other options listed.