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. Yacold 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 Yachtold, 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's 60 Second Science.

I'm Suzanne Bard.

If you watch nature documentaries, it's easy to come away with the impression that lush tropical forests have been largely undisturbed until modern times.

Tropical forests have sort of long been considered to be these pristine wildernesses that humans haven't really touched until recent industrial forces have started to invade them and challenge them

with 21st century capitalism.

Archaeological scientist Patrick Roberts of the Max Planck Institute for the Science of Human

History.

However, in the last two decades, archaeological data have

shown that actually human societies have occupied and modified these environments over many millennia.

Robert says some of the trees alive in tropical forests are up to a thousand years old,

and they're sort of like time capsules, storing a record of past human activity in their tree rings, chemistry,

and DNA.

So we wanted to see how different existing methods might come together to explore past tree

populations, tree growth, tree ages, by looking at the largest witnesses of the changes in

human activity in the tropics, the trees themselves. For example, indigenous

peoples of the Amazon Basin cultivated Brazil nuts for thousands of years. Robert's colleague,

...