Read the passage. Paragraph 1: Testing food for space travel sounds like a matter of calories and packaging, but the menu team begins with a more human question: what will still feel like a meal when the table, weather, and ordinary kitchen smells are gone? Paragraph 2: Taste panels rate texture after reheating, but they also discuss color, memory, and whether a dish can break the sameness of a long mission. A stew that is nutritionally efficient may fail if no one wants it twice. Paragraph 3: The work reveals that food is part of morale, not just fuel. In a sealed habitat, a familiar flavor can become a small form of place. Paragraph 4: A menu, then, is another life-support system, though not one measured only in grams. What structural purpose does Paragraph 1 serve in the passage about astronaut menu testing?