Vocabulary Challenge Ⅱ--Puzzle

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Across
  1. 4. The natural world around us, including air, water, land, plants, and animals. (11 letters)
  2. 7. The process of becoming modern or more developed. (13 letters)
  3. 8. To feel sad or disappointed about something that has happened or that you have done. (6 letters)
  4. 9. Not making any sound. (6 letters)
  5. 10. A suggestion about what someone should do. (6 letters)
Down
  1. 1. To keep safe from harm or injury. (6 letters)
  2. 2. Sure of oneself and one's abilities. (8 letters)
  3. 3. Having the duty to take care of something or someone. (11 letters)
  4. 5. To think of someone or something in a particular way. (6 letters)
  5. 6. A real fact or piece of information. (5 letters)