General question

123456
Across
  1. 3. Famous British rock band
  2. 4. An area of land protected by wildlife (4 letters)
  3. 6. A common insect known for its buzzing (3 letters)
Down
  1. 1. Element with the symbol 'O' (6 letters)
  2. 2. A large, predatory fish (5 letters)
  3. 5. A written work or composition, often of a scholarly nature (7 letters)