Brain-on-a-chip. Dazzling in green and magenta this image shows the nerve fibres (in green) produced by neural stem cells (in magenta) as they grow on a synthetic gel. Captured by a technique known as confocal microscopy, the image is part of research shedding light on how tinkering with the environment can affect the way in which nerve fibres grow. (Photo by Collin Edington and Iris Lee/Massachusetts Institute of Technology/Wellcome Images)

Law enforcement officers clash with protesters, Wednesday, July 20, 2016, in Cleveland, during the third day of the Republican convention. (Photo by John Minchillo/AP Photo)

Kendall Jenner seen at Universal, NBC, Focus Features, E! Entertainment Golden Globes After Party Sponsored by Chrysler on Sunday, January 8, 2017, in Beverly Hills, Calif. (Photo by Eric Charbonneau/Invision for Focus Features/AP Images)

Giant panda Ying Ying rests on a rock in its enclosure while a visitor takes a selfie at Ocean Park in Hong Kong, China, 24 September 2020. An An turned 35 in August. Giant pandas in the wild can live up to 20 years on average, while lifespans of those under human care can reach over 30 years. (Photo by Jerome Favre/EPA/EFE)

A mannequin wearing a face mask and nurse's uniform stands next to a sign supporting the NHS, stands in a field during the Covid-19 pandemic on October 06, 2020 in Northwich, United Kingdom. (Photo by Christopher Furlong/Getty Images)

A diving competitor during a practice session at Tokyo Aquatics Centre ahead of the Tokyo 2020 Olympic Games in Japan on Wednesday, July 21, 2021. (Photo by Stefan Wermuth/Reuters)

Switzerland's cyclist Marlen Reusser reacts after placing second in the women' elite time trial race of the UCI World Championships Road Cycling Flanders 2021, in Bruges, on September 20, 2021. UCI World Championships Road Cycling Flanders 2021 takes place from September 19 until September 26, 2021, in several cities in the Belgian region of Flanders. (Photo by Simon Wilkinson/BELGA via AFP Photo)

YouTube personality Jake Paul (L) fights former UFC welterweight champion Tyron Woodley at the Amalie Arena in Tampa, Florida, on December 18, 2021. (Photo by Kim Klement/USA TODAY Sports)