Serendip is an independent site partnering with faculty at multiple colleges and universities around the world. Happy exploring!
Remote Ready Biology Learning Activities has 50 remote-ready activities, which work for either your classroom or remote teaching.
more on "nice spacing"
Different computer/web browser combinations unfortunately interface differently with current Serendip software (drupal). The combination of macintosh and safari is particularly bad. If you're working with a mac, try firefox instead. More generally, try fiddling a bit with whatever you're working with and with options below if you're having trouble getting things to look the way you want them to.