natural selection

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Across
  1. 3. change in gene structure
  2. 4. reproductive success
  3. 6. variation in general frequency
  4. 8. a vary in genes
  5. 9. ratio of alleles
Down
  1. 1. some individuals have better traits
  2. 2. an event that gets rid of many animals
  3. 5. changing to adapt to environment
  4. 7. genes passed down