It's the only vegetable or fruit that is never sold frozen, canned, processed, cooked, or in any other form but fresh. What is it?

Lettuce is highly perishable and has a delicate texture that doesn't hold up well to freezing, canning, or processing. It becomes wilted, mushy, or loses its crispness when processed. While other vegetables like tomatoes, cabbage, and brinjal (eggplant) can be preserved in various forms, lettuce is almost exclusively sold fresh.