What is a common use of cotton by-products?

The correct choice highlights a significant application of cotton by-products, which include both the residual materials from cotton processing and the components derived from the cotton plant itself. Cotton by-products, such as cottonseed, are valuable in several industries. The seeds can be processed to extract oil, which is used not only in culinary applications but also in the production of various consumer goods, including soap and cosmetics. Additionally, cottonseed meal, a by-product of the oil extraction process, serves as a nutritious animal feed, particularly for livestock, due to its high protein content. This dual utilization of cotton by-products for both animal nutrition and oil production underscores their economic significance and the sustainable nature of the cotton industry, where nearly every part of the plant is leveraged effectively.

The other options, while they may seem plausible, do not align as closely with common uses of cotton by-products. Biodegradable plastics have various sources and while research is ongoing, they are not predominantly derived from cotton. Similarly, while textiles do involve dyes, they are not primarily categorized under by-products but rather as direct components of the cotton processing chain. Construction materials might incorporate some fibers, but this is much less common compared to the direct uses in feed and oil.