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A kind of evergreen tree in Chile is increasingly important for producing new vaccines.
Immune System
The quillay tree has a kind of molecule that helps the body’s immune system. Vaccine makers need only a tiny amount of the substance to produce a single treatment. But the tree’s rarity has them worried about future supplies.
The immune system is the body’s natural defense system against infections and diseases. It includes white blood cells and antibodies designed to fight foreign substances in the body.
*This article has been edited and reprinted from VOA Learning English with permission from Voice of America (VOA) for use in English language materials.