Plant resins are sticky substances produced by various trees and plants, primarily as a defense mechanism against injury or infection. These natural compounds can be found in species like pine and frankincense, and they often have a pleasant aroma. Resins can harden when exposed to air, forming a protective barrier that helps the plant heal. Humans have utilized plant resins for thousands of years. They are commonly used in products like incense, varnishes, and adhesives. Additionally, some resins, such as amber, are valued for their beauty and are often used in jewelry. Their versatility makes them important in both nature and human culture.