The correct answer is Isoprene. Explanation & Key Takeaways: • Natural rubber is a polymer of isoprene. Related Concepts: • Natural rubber, also called India rubber, latex, Amazonian rubber, caucho, or caoutchouc, as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds, plus water. • Thailand and Indonesia are two of the leading rubber producers. • Types of polyisoprene that are used as natural rubbers are classified as elastomers. • Currently, rubber is harvested mainly in the form of latex from the rubber tree (Hevea brasiliensis) or others. • The latex is a sticky, milky colloid drawn off by making incisions in the bark and collecting the fluid in vessels in a process called "tapping". • The latex then is refined into the rubber that is ready for commercial processing. • In major areas, latex is allowed to coagulate in the collection cup. • The coagulated lumps are collected and processed into dry forms for sale. • Natural rubber is used extensively in many applications and products, either alone or in combination with other materials. • In most of its useful forms, it has a large stretch ratio and high resilience and is extremely waterproof.