QRP code breaker

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Across
  1. 4. German full form of bmw:
  2. 5. what did bmw manufacture before cars?
  3. 6. Which is the most repeated starting letter among all the words hidden in the picture?
  4. 7. what has hands but can't clap
  5. 9. Spots, tops, pots, opts, .....
  6. 10. The brand with most expensive car in the world:
Down
  1. 1. 8 - 7 - 3 x (-4) = ? :
  2. 2. Answer the riddle: what is so fragile that simply saying it will break it?
  3. 3. fruit riddle: I am dressed in red and have got a stone in my throat, what am I?
  4. 4. What is black when it’s clean and white when it’s dirty?:
  5. 8. Biggest BMW production plant in Europe