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.
websites
Here are some websites to check out... not all include online activities... they are mostly directed toward middle school science curriculum:
http://www.k12science.org/curriculum/drainproj/information.html
http://library.thinkquest.org/J002289/meta.html
http://pbskids.org/zoom/games/3puckchuck/
http://www.educationworld.com/a_curr/curr019.shtml