Early signs of Alzheimer's disease may be hidden in the way a person speaks, but it's not yet clear which details of our diction are most critical for diagnosis.
When a virus jumps to humans from another species, it can seem like a supervillain bent on world domination - especially if it goes on to ignite a pandemic, as many zoonotic viruses have done in recent decades.
Comb jellies - very simple, gelatinous creatures best-known for their hypnotic underwater light shows - first appeared in Earth's oceans around 550 million years ago.