Sen. Rob Portman, R-Ohio, seen here in an October press conference, has announced he won't run for reelection in 2022, citing hyper-partisanship in Congress. Graeme Jennings/Pool/AFP via Getty Images hide caption

Registered Nurse Shyun Lin, left, administers Alda Maxis, 70, the first dose of the COVID-19 vaccine at a pop-up vaccination site in the William Reid Apartments in Brooklyn, N.Y., on Jan. 23. Mary Altaffer/AP hide caption

Representatives from the Retail, Wholesale and Department Store Union hold a pro-unionization sign outside Amazon's warehouse in Bessemer, Ala. Miranda Fulmore/WBHM hide caption

Naked mole rats are very communicative creatures, they quietly chirp, squeak, twitter or even grunt to one another. The scientists wanted to find out whether these vocalizations have a social function for the animals – and found that each colony has its own dialect that promotes social cohesion. Felix Petermann, MDC hide caption

The Pfizer-BioNTech COVID-19 vaccine requires storage in extremely frigid temperatures before it's thawed out for use. Moderna's vaccine also must be stored in very cold temperatures. Noah Berger/AP hide caption

Facebook created the panel of experts to review the hardest calls the social network makes about what it does and does not allow users to post. Jeff Chiu/AP hide caption

Nurse Vash Deelchand inoculated Kate Bingham, chair of the U.K. government's vaccine task force, with a Novavax vaccine at the Royal Free Hospital in London in October. Kirsty O'Connor - PA Images/PA Images via Getty Images hide caption

Cicely Tyson attends the TIME 100 Gala in 2012. The famed actress died at the age of 96. Tyson inspired generations of African American actors who grew up watching her perform on stage and on screen. Fernando Leon/Getty Images for TIME hide caption