Drag the tiles to the boxes to form correct pairs. Raya is a gardening enthusiast who is looking to buy a new house. She wonders whether her house plants will grow well if she buys an apartment on a higher floor. She remembers that her friend Jenn also has a small garden on her balcony, and her plants seem healthy. Raya conducts an experiment to study the effect of altitude on the growth of plants. She gathers plant samples and places them on five different floors of a 20-story building. Identify the basic components of Raya’s experiment, including the confounding variable.