The correct answer is option 1: "shed their leaves every year." Deciduous trees are a type of tree that loses their leaves annually. They go through a process called "leaf abscission" where the leaves are deliberately shed as a survival strategy during the cooler months. This is a way for the tree to conserve energy and protect itself from the harsh winter conditions. Shedding their leaves also allows deciduous trees to conserve water and nutrients, which can be stored in the trunk and branches during the dormant period. Unlike evergreen trees, which retain their leaves year-round, deciduous trees shed their leaves and then grow new ones in the spring. This cycle of leaf growth and shedding is characteristic of deciduous trees.