You know why? Genes.

They are these little pieces of code that determine the characteristics of living things, and all living things have them.

But genes can be changed, they can be modified, and that`s how you end up with a GMO, a genetically modified organism.

Some companies modify the genes of animals and plants that are part of our food chain.

Over the weekend protests like this one happened at dozens of countries around the world.

Two million people protesting against GMOs.

And against one specific company that makes them.

Jake Tapper digs into the details.

JAKE TAPPER, CNN CORRESPONDENT: Some opponents of these GMOs want them banned.

Others say foods whose DNA has been changed need at least to be labeled.

Monsanto is the leading producer of genetically modified seeds and herbicides.

In the last quarter alone, Monsanto sold seed, much of it modified, worth more than $4 billion.

It`s a business, the company says, that is helping to feed the planet.

UNIDENTIFIED MALE: It`s a vision that strives to meet the needs of a rapidly growing population.

TAPPER: But the protesters want to know just how their food is being re- engineered.

Some of the outrage was sparked by these shocking photos showing massive tumors that developed on these rats after they ate genetically modified corn over their lifetimes.

But that study by researchers at the University of Cannes (ph) in France has been criticized by many in the scientific community and by the European Food Safety Authority,

who say it is simply not up to scientific standards.

Even so, the disturbing tumor photos did lead many to question their own standards about what exactly we`re all eating.

One question, how can you know if you`re eating genetically modified foods and feeding them to your family?

Well, you can`t. And that`s the issue.

UNIDENTIFIED MALE: I received over 2,200 letters on this topic.

TAPPER: Last week, senators debated whether states could require food labeling for products with genetically engineered ingredients.

SEN. BERNARD SANDERS, I-VERMONT: The concept that we`re talking about today is a fairly common sense and non-radical idea.

TAPPER: The legislation, introduced by independent Vermont Senator Bernie Sanders, failed.

SANDERS: When you take on very powerful biotech companies like Monsanto and large food corporations,

who in many ways would prefer that people not know what is in their food that they produce, they are very powerful.

TAPPER: And this comes on the heels of what critics call the Monsanto Protection Act.

That`s legislation passed by Congress and signed by the president earlier this year,

a bill that allows genetically modified crops approved by the Agriculture Department,

to be grown even if there is action in the courts declaring them to be dangerous.

On its web site, Monsanto states, quote, "plant biotechnology has been in use for over 15 years without documented evidence of adverse effects on human or animal health, or the environment."

Legislators who sided with Monsanto say the company is improving on nature.

UNIDENTIFIED MALE: I think it would be more accurate called a modern science to feed a very troubled and hungry world.

UNIDENTIFIED FEMALE: Today`s first "Shoutout" goes out to Mrs. Hansey`s (ph) history and government classes at Layton (ph) High school in Layton, Utah.

Where will you find the city of Timbuktu?

Here we go. Is it in Asia, Africa, South America or nowhere? It`s fictional?

You`ve got 3 seconds, go.

Timbuktu is a real place, and it`s located in the West African nation of Mali.

That is your answer and that`s your Shoutout.

AZUZ: Timbuktu was the center of Islamic culture, and its famous library was home to hundreds of thousands of important documents and manuscripts.

When violence broke out there earlier this year, there was concern that those documents might be destroyed.

But most of them had already been smuggled out.

UNIDENTIFIED FEMALE: To get the manuscripts out, we packed them very tightly in footlockers, which are metal boxes, much like what you see in the army.

And as people began to understand what they were carrying, they said we want to help.

They would offer all kinds of help just because they felt very strongly that this was their heritage as well.

AZUZ: So the documents are safe, right?

Not necessarily. Now they are facing a new threat.

The manuscripts went from Timbuktu, which is on the edge of the Sahara desert, to southern Mali.

The climate there more humid.

The paper is showing signs of mildew and rot, and southern Mali`s rainy season is just weeks away.

Next up today, brains.

They send out impulses that control our movements and motor skills.

Last week, brain surgeons were installing a device to help a patient control tremors in his hand.

To see if it was working, doctors woke him up during surgery and had him do some tests.

UNIDENTIFIED MALE: My music is really important to me, so I am hoping that this will allow me to do that, to play guitar.

I`m a finger picker, I want to get back to that.

I had just been putting it off, trying to figure out why this is happening.

So hopefully this is going to help that.

UNIDENTIFIED MALE: What we saw was a level of precision and a level of control that he has not experienced in years.

And that second stage is when we implant the generator that actually sends the electrical impulses to his brain.

AZUZ: Cindy Corcoran (ph) and her mother were both injured during the Boston marathon terrorist bombing last month.

They both survived, but they had severe injuries.

Cindy is 18, a senior in high school, and while she and her mother were recovering,

Cindy had her sights set on some upcoming milestones.

Senior prom, her high school graduation. She wanted to get to both.

Cindy didn`t just make it to prom; she was crowned prom queen.

UNIDENTIFIED FEMALE: When I was in the hospital, I didn`t think that this was going to be possible.

Oh my gosh, the rehab and I just - because I was up and I was doing (inaudible),

more like I could do it, and it was a goal, like this graduation (inaudible).

UNIDENTIFIED FEMALE: Today, "Shoutout" extra credit goes out to Ms. Carlton`s (ph) students at the Black River public school in Holland (ph), Michigan.

Now, which of these is arthropod?

You know what to do. Is it a squid, ant, slug or mushroom?

Rewind that clock to 3 seconds and go.

Arthropods have joint limbs, and the only option with those is an ant.

That`s your answer and that is your "Shoutout" extra credit.

AZUZ: Crazy ants. Sounds like a children`s toy or your mother`s eccentric sisters.

But these things are a lot less fun.

Tawny crazy ants are native to South America, they are invasive in North America, and they are quickly making themselves at home.

They have turned up in Texas, Mississippi, Louisiana, and Florida.

They travel well, unfortunately, so they could have arrived here on ships.

Their scientific name is Nylanderia fulva, which is why I`m calling them crazy ants.

The other reasons, they can colonize in huge numbers, take over food sources, leaving nothing for other species to eat, and they are omnivores.

If another ant crosses them, the crazies will attack and destroy.

This could have a significant impact on North American ecosystems. Plus.

UNIDENTIFIED MALE: These ants will come into your house, they nest in your crawl spaces and in your walls.

And they reach very high abundances in your house.

AZUZ: And they make terrible pets.

They like to nest near electrical equipment, like the switchbox in your house or the wiring in your car.

They can short that out, and that`s just one reason why they`re crazy.

These things are quick to swarm, their trails are haphazard and wide, and they are hard to get rid of.

Can you call an exterminator? Yes.

Can they kill crazy ants? Yes.

Could the ants come back? That`s the kicker.

UNIDENTIFIED MALE: You kill the ants in this spot and they just flood in from the surrounding habitats.

So the ability to control them is really limited.

AZUZ: And don`t think poisoned bait will send them packing to that great anthill in the sky.

Tawny crazy ants won`t eat it.

People who have been infested say they want their fire ants back.

The good news is, crazy ants don`t sting you like fire ants, which is why you can watch this and not hear screaming.

The bad news is, well, that`s about the only good news.

There is something we can do or not do.

Reproductive crazy ants don`t fly.

They hitch rides with humans to new areas.

So if we can make sure that plants are ant-free before we transport them,

that our cargo is free of ants before we travel,

we may be able to keep the pests from spreading.

Otherwise there is no telling what end there will be to their antics.

Before we go today, we want you to see a superlative symbol.

This is the flag of Romania.

This one might not look like much when you`re up close but take a step back and you start to get some perspective.

This isn`t just any flag; it`s the largest flag in the world.

11,045 feet by 744 feet. It took 44 miles of thread to make the thing and 200 people to help roll it out.

It`s too heavy to actually flutter in the wind, but when it comes to formidable flags,

thanks to its banner achievement, that one has taken over the poll position.

It`s time for us to fly, we`ll see you tomorrow on CNN STUDENT NEWS.

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