The study of extremophiles—organisms that thrive in conditions fatal to most life—has expanded our understanding of biological resilience.
For example, the bacterium *Deinococcus radiodurans* can withstand radiation doses thousands of times greater than humans can. _______, tardigrades, also known as water bears, can survive the vacuum of space, extreme temperatures, and intense radiation.
Which choice completes the text with the most logical transition?
