The immune system is so cool and so important but it largely goes about its business without us knowing it. In this episode you'll get a front row seat as our immune cells (aka friendly monsters) fight off bacteria and viruses (aka bad robots). We'll also find out how vaccines provide important training for our immune cells. Plus, co-host Colin quizzes Molly on immune system facts and there's a brand new mystery sound! This episode was brought to you by Indeed (<a href="https://indeed.com/BRAINSON" class="default">indeed.com/BRAINSON</a>) Interlochen Center for the Arts (<a href="https://interlochen.org/brainson" class="default">interlochen.org/brainson</a> Code: SAVE10) Staples Connect (<a href="https://staplesconnect.com/printbig" class="default">staplesconnect.com/printbig</a>) Little Passports (<a href="https://littlepassports.com/BRAINS" class="default">littlepassports.com/BRAINS</a>)

Why are butts and poop so funny?

Brains On!® is a science podcast for curious kids and adults from American Public Media. Each week, a different kid co-host joins Molly Bloom to find answers to fascinating questions about the world sent in by listeners. Like, do dogs know they’re dogs? Or, why do feet stink? Plus, we have mystery sounds for you to guess, songs for you to dance to, and lots of facts -- all checked by experts.