Hello, I'm Neil McCarthy. Just before the documentary starts, I want to bring you up to date with my podcast because a lot's been happening during the last few weeks.

Death in Ice Valley has become quite popular around the world, and thanks if you've downloaded it, and our investigation is progressing as we try to piece together as much as we can about the life of a woman whose body was found in Norway in 1970.

It's becoming a Cold War mystery. There are now seven episodes to catch up on. Search for Death in Ice Valley.

Hello, I'm James Wong. I'm a botanist, and here on the BBC World Service, I'm asking a peculiar question.

Is eating plants wrong?

This is a vegan restaurant in trendy West London, and it's packed out even on a Wednesday night with people who don't eat animals to avoid harming sentient, intelligent organisms.

Eating animals kind of grosses me out, and I don't see the difference between eating somebody's pet cat and eating a cow.

I feel it's too unfair to kill somebody for just your taste buds.

But what if I told you that plants can not only sense the world around them, but according to some scientists, can learn, remember, make decisions and even engage in complex communication with the species that surround them.

Plants are much more than just passive things rooted at the spot, a sort of backdrop to the natural world.

And that's what we'll explore in this programme.

I'll be delving into the intriguing new science that's revealing that plants, capable of doing all sorts of things, once thought to be the exclusive preserve of animals, or even humans.

Raising the question, is it right to eat plants?

Now let's get one thing clear from the start.

Plants don't have brains, they don't have nerves, they don't even have nerve receptors, but they can detect information from the world around them in a variety of ways.

Here's Rick Carbon from the University of California at Davis.

Without eyes, plants can perceive a lot of information about light, without noses, plants can perceive chemical information, without ears, plants can perceive sounds.

And so we've come to realise that plants are very perceptive about what's going on in their environments.

You could argue, for example, that plants can perceive most of the senses that humans can.

I would agree with that, and then some.

Plants can perceive electrical signals, they can respond to vibrations, for instance, feeding caterpillars that are walking across their hairs.

We know, for instance, anyone who's had a dog knows that dogs have a much keener sense of smell than humans do.

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