The correct answer is - he wanted to be sure before considering before the bird as a new type if it really represents new species.
Explanation:
Dr. Smith has found the bird that he considered as new species however Dr. Wilson said he will only be convinced if DR. smith could find several members of the same species. Dr. Wilson seems to be sure before considering the bird that Dr. smith found as the new species. It is because he wants to sure if it's not an unusual example of the pre-described species.
Thus, the correct answer is - he wanted to be sure before considering before the bird as a new type if it really represents new species.
Explanation: this is because they need to retain water. The piscine kidney cannot afford to produce a urine of higher concentration than the fluids in the body so production is kept at minimum.