In this Back To School episode we consider the "List of Life": the criteria that define what it is to be a living thing. Some are easy calls: A kitten is alive. A grain of salt is not. But what about the tricky cases, like a virus? Or, more importantly, what about futuristic android robots? As part of our Black History Month celebration, developmental biologist Crystal Rogers and scientist-in-residence Regina G. Barber dig into what makes something alive, and wade into a Star-Trek-themed debate. Is there something you'd like us to cover in our Back To School series? Email us at shortwave@npr.org.This episode was produced by Berly McCoy, edited by Gabriel Spitzer and fact-checked by Anil Oza. The audio engineer was Josh Newell. Learn more about sponsor message choices: podcastchoices.com/adchoicesNPR Privacy Policy