Liz wants to badly to say that it's possible, but may not be possible yet with the tools of the human trade. Humanity isn't quite there, but the Antarians were able to do it. They were able to sample Human DNA and hybridize it with their own, creating Human-Antarian Hybrids in Max, Michael, Isabel, and Tess. And those abilities that the Antarians possessed transferred to the human forms they took. It's not just human talent in them, it's the alien royal family they were once a part of, too.

Instead she smiles, clearly fascinated for what she feels are not entirely disingenuous reasons. She liked science before she got caught up with aliens.

"Being able to regrow a limb would mean the world to the military, nevermind all those kids who are born without them. How far did he get in his research, if it's okay to ask?"

She senses that the 'was' means something happened. People don't use past tense unless things are in the past. Were. Liz isn't tactless enough to ask that question.