Official Explanation
Blank (i) is explained by the part of the sentence after it, specifically, “which will greatly enhance the ability... . ” So, veritable (true; correct) information makes the rest of the sentence logical.
Blank (ii) is explained by the preceding portion of the next sentence “But given human nature ... age misreporting,” which implies that there is a problem that can be solved with age validation, which is therefore a requisite (necessary) process.
Blank (iii) is explained by the sentence containing blank (ii), which mentions “exceptional longevity research.” Therefore, it is logical that these claims need a significant validation procedure, making consummate (complete) a good choice, and the only choice that could work ( cavalier means dismissive and jackleg means lacking skill).
Answer: A,E,G