Keto: what’s the science behind the diet?

‘Parasites should get more fame’: the nominees for world’s finest invertebrate

Streams of medicines: what’s hiding in the UK’s waterways?

Streams of medicines: how Switzerland cleaned up its act

What 40 years as Observer science editor has taught Robin McKie

RFK Jr’s mixed messages on vaccines

Is ‘de-extinction’ really possible?

Evidence of alien life, a clue about the rise of bowel cancer, and a new colour?

Why did Just Stop Oil just stop?

Why did Spain and Portugal go dark?