Why do we have body odour?

Why do we have body odour? Can weeds be useful? Could marine animals learn not to eat plastic in the ocean? How does your body warm up when you're swimming in cold water? Why does my dog twitch to a particular sound? If an aeroplane followed the path of a laser beam, would it end up in space? Is time just an illusion? Plus, the science behind a possible insulin pill. Chris Smith joins Eusebius McKaiser to answer your science questions... Like this podcast? Please help us by supporting the Naked Scientists