Passage Summary: Brianna argues that they should have bought their tree a year earlier because it would have had time to grow strong roots and wouldn't be dying in the current drought.

Conclusion: Purchasing a tree last summer would have been a better choice than purchasing one this summer.

Reasoning: A tree bought last year would have benefited from normal rainfall to establish roots, making it better equipped to survive the current drought than the struggling tree bought this year.

Analysis: To identify the conclusion, we look for the statement that receives support from the rest of the text. The first sentence is the main claim, while the subsequent sentences provide the botanical evidence regarding root development and drought resistance to justify that claim. The word 'because' in the third sentence explicitly marks the transition from the conclusion to the supporting premises.