Noone can clarify my doubts! challange

I've some doubts.. Can u please clarify me..
1. When dog food is new and improved tasting, who tests it? (to be given a thought)

2. If the "black box" flight recorder is never damaged during a plane crash, why isn't the whole airplane made out of that stuff? (very good thinking)

3. Who copyrighted the copyright symbol? (who knows)
4. Can you cry under water? (let me try)

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