Leaves need to be elevated so they are exposed so they are exposed to sunlight for photosynthesis. Which part of the stem grows to make this possible?

The correct answer is apical meristem"

A stem is one of two main structural axes of a vascular plant, the other being the root. The stem is normally divided into nodes and internodes. The nodes hold buds which grow into one or more leaves, conifer cones, roots, other stems, or flowers (inflorescences); the internodes distance one node from another.