Alkenone molecules from phytoplankton are robust enough to survive the effects of weathering and chemical breakdown for 110 million years. Rock layers yield chemical traces of these ancient organisms. Their chemical composition indicates ancient water temperatures.
Sulfa drugs, such as antibiotics that contain sulfonamides. Example: Some combination drugs such as Sulfamethoxazole-trimethoprim (Septra, Bactrim) and Erythromycin-sulfisoxazole contain sulfonamides. <span>