spinach
watermelon
I'm not positive, but I've never seen canned or frozen cucumbers:)
Lettuce
Lettuce
No, It Was Sold Though.
Yes, broccoli can be frozen and is often sold this way at supermarkets.You can freeze this vegetable. You need to blanch it first. Blanching means to submerge the vegetable in boiling water for a few minutes. After blanching, give the vegetable a bath in ice water to stop the cooking process. Drain the vegetable, place in an airtight container and freeze.
Any vegetable (roots or greens) need to be prepared and then either cooked, or used in a salad. Vegetables come from farms where they are collected and stored. They are shipped to supermarkets where they are sold. The meal is prepared, then voila! The vegetables on your plate.
The likely answer is watermelon. However, there are commercially available dried watermelon chips, and these can be made at home (although they may have limited shelf life). Pickled watermelon rind is also sold in some areas.
It is possible to buy raw beetroot but people prefer to buy it already cooked because peeling and preparing beetroot for cooking can stain your fingers and clothes.
lettuce
Lettuce
Yes, it is packaged and sold to be cooked and eaten.