Detailed Instructions: Given a scientific passage and an answer, generate a question for the given answer.
Problem:Passage: Stems are organs that hold plants upright. They allow plants to get the sunlight and air they need. Stems also bear leaves, flowers, cones, and smaller stems. These structures grow at points called nodes. The stem between nodes is called an internode. (See Figure below . ). Answer: stem
Solution:
What is the basic structure that holds plants upright, allowing plants to get the sunlight and air they need?