The conclusion of the argument is: that recent property development bordering a national park has not adversely affected the park's wildlife.
Why? A comparison of the most recent survey of the park's wildlife with one conducted just prior to the development shows that the amount of wildlife has in fact increased over the intervening decade. We are also told that the park's resources can support its current wildlife populations without strain.
Answer choice (A): "While both surveys found the same species of animals in the park, the more recent survey found greater numbers of animals belonging to each species."
This answer choice strengthens the fact that no specific species was harmed by the recent property development. For instance, the wildlife population could have increased because one species was greatly benefitted, but another was harmed. If this were the case, then the property development did adversely affect at least one species of the park's wildlife. But, answer choice (A) strengthens the argument by clarifying that the number of species stayed the same--so it was truly the populations of each species that increased, as opposed to only one species increasing while the others were harmed.
Hope that clears things up! Please let us know if you have any other questions.
