For the next example, I wanna talk about crops that are resistant to insects. We can use cotton as an example. The boll weevil and other insects can completely destroy yields of cotton crops, but the bacteria Bacillus thuringiensis kills insects due to a toxin that punches holes in the cell membranes in the stomach of the insect. Now this toxin of the bacteria, it's called the BT toxin, it only works in an alkaline environment. And the gut of insects is alkaline, that's the exact opposite of the pH of our own gut, which is acidic. For this reason, the BT toxin is safe to humans. And indeed, the Bacillus bacteria has been used for years in organic agriculture to combat insects, because it kills the insects. Humans are allowed to eat this bacteria, because the toxin does not affect us. So you have a bacteria, which can kill an insect. Thus, saving the crop and having no effect on human physiology. What can we do with genetic engineering? With genetic engineering, we can take the exact gene for the toxin out of the bacteria. Place it inside the cotton and now the cotton will be naturally resistant to the insect. In organic agriculture, you add the entire bacteria. In genetic engineering, we add just the gene for the toxin. Both of them contain the toxin. One contains the toxin within the bacteria, the other contains just the gene for the toxin. So this transgenic plant becomes naturally resistant to the insects and you can see that this works very well. Here we have two crops, one next to the other. One is transgenic, expressing the BT toxin. The other is not transgenic, so it is completely sensitive to the insects. You can see the difference in yields between the two fields. So the question is, is this good? Well, aside from increasing yields, what this does is it reduces the amount of pesticides that the farmer needs to use. In modern agriculture, the way that farmers deal with insects is through pesticides that are made from petro chemicals. These petro chemicals are poisonous, and go into the groundwater. The accumulative reduction in pesticide use since BT cotton was introduced between the decade of 1996 and 2005 was a reduction in 224 billion tons of active ingredient. That means there are less poisons in our soil, less poisons in our ground water and it also saves petroleum that was used to make the pesticides. There's another effective, the adoption of the BT Cotton. The chemical pesticides that are normally use are poisonous to the farmers, to the humans who are using them. In China, for example, in the year 2000, 29% of the farmers who did not use transgenic cotton, a BT cotton suffered from pesticide poisoning, but only 7% of those who did use transgenic cotton were poisoned. As an added bonus, the yield of the transgenic crop was 50% higher than that of the non-transgenic crop and the revenue was over 400% higher. So not only is this good for the environment, this is good for the farmer. He's less exposed to poisons and he's getting a higher yield.