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 high water content, making it unsuitable for freezing, canning, or most processing methods without significant texture and quality loss. It is almost exclusively sold fresh. While other vegetables like carrots and sweet potatoes are commonly frozen, canned, or processed, lettuce is always sold fresh.