Understanding the human body is a team effort. That's where the Yachtel group comes in.

Researchers at Yachtolt have been delving into the secrets of probiotics for 90 years.

Yachtold also partners with nature portfolio to advance gut microbiome science through the global grants for gut health, an investigator-led research program.

To learn more about Yachtolt, visit yawcult.co.j.p.

That's y-A-K-U-L-T dot-C-O-J-P.

When it comes to a guide for your gut, count on YacL.

This is Scientific American 60-second science.

I'm Julia Rosen.

We all know the story. Sixty-six million years ago, a giant asteroid crashed into Earth,

killing off three quarters of all species, including most of the dinosaurs.

Researchers suspect that the impact caused the extinction by kicking up a cloud of dust and tiny droplets

called aerosols that plunged the planet into something like a nuclear winter.

And these components in the atmosphere drove global cooling and darkness that would have stopped

photosynthesis from occurring, ultimately shutting down the food chain.

Shelby Lyons, a recent PhD graduate from Penn State University.

But scientists have also found lots of soot in the geologic layers deposited immediately after the asteroid impact,

and the soot may have been part of the killing mechanism too, depending on where it came from.

Some of the soot probably came from wildfires that erupted

around the planet following the impact, but most of these particles would have lingered in the lower

atmosphere for only a few weeks and wouldn't have had much of an effect on global climate.

But scientists hypothesized that soot may also have come from the very rocks that the asteroid pulverized when it struck.

If those rocks contain significant amounts of organic matter, such as the remains of marine organisms,

...