How do you detect a particle that emits no light - in other words, something invisible? This is the intriguing challenge faced by scientists hunting for 'dark matter'. In our series finale, we talk to Elizabeth Bloomfield from Oxford's Department of Physics about dark matter, how we know it exists, and why her research is taking her deep beneath a mountain in Italy in the quest to find it.

What's the best gift you can give? To the millions of people whose lives have been saved by complete strangers, the answer would be simple: blood. But what exactly happens when blood has been donated, and how do we know it is safe? We chat to Dr Richard Mayne from Oxford's Experimental Medicine Division about genomics, Next-Generation Sequencing, blood screening (...and Star Trek).

Could you be a blood-donating hero? Blood stocks are currently critically low, with the NHS Blood and Transplant (NHSBT) group in urgent need of new donors. Click here, and you'll be on your way to saving lives: https://www.blood.co.uk/news-and-campaigns/campaigns/blood-donor-appeal/

Whether you've been served an advert for it, or just heard about it in the media, it's likely that 'Ozempic' isn't a totally unfamiliar word. Now often associated with weight-loss, Ozempic is actually the brand name for a drug used to treat diabetes. So what exactly is it, how does it work, and is it safe? We chat to diabetes and endocrinology (hormone) expert Dr Annie de Bray to find out.