Choose the sentence in this excerpt that provides evidence of tangible results of chemistry research.
1. Many chemists and materials scientists work in basic and applied research.
2. In basic research, chemists investigate the properties, composition, and structure of matter.
3. In applied research, chemists investigate possible new products and ways to improve existing ones.
4. Chemistry research has led to the discovery and development of new and improved drugs, plastics, cleaners, and thousands of other products.
The correct sentence is:
4. Chemistry research has led to the discovery and development of new and improved drugs, plastics, cleaners, and thousands of other products.
Explanation: This sentence explicitly states the outcomes of chemistry research, listing specific tangible results, such as new drugs and improved products, which demonstrates the practical impacts of the field.