Answer: A.They contain plants that purify water.
The active site is complementary to its substrate due to its specific 3D structure. The substrate fits in to one specific active site so an enzyme will only bind to one substrate. They are SPECIFIC. Lock and key theory.
I believe the correct answer would be Tapeworm and cat
Question 13 should be marine
The answer is C, or Adaptations increase the chances that an individual will reproduce and pass its genes onto the next generation. Such traits then become more common within a population.