Question

pine trees have cones instead of flowers, and their seeds are unprotected. what structure are pine trees most likely missing?
roots
leaves
fruits
stems

Explanation:

Pine trees are gymnosperms. In angiosperms (flowering plants), fruits develop from the ovary after fertilization and protect the seeds. Since pine trees have unprotected seeds (naked seeds as in gymnosperms) and no flowers (which are precursors for fruit - formation in angiosperms), they lack fruits. Roots, leaves, and stems are common plant structures present in pine trees.

Answer:

fruits