Input: Article: Believed to be a stowaway on a U.S. military transport near the end of World War II, the brown tree snake (Boiga irregularis) was accidentally introduced to Guam, that previously had no native species of snake. It nearly eliminated the native bird population. The problem was exacerbated because the reptile has no natural predators on the island. The brown tree snake, known locally as the kulebla, is native to northern and eastern coasts of Australia, Papua New Guinea, and the Solomon Islands. While slightly venomous, the snake is relatively harmless to human beings. Although some studies have suggested a high density of these serpents on Guam, residents rarely see the nocturnal creatures. The United States Department of Agriculture has trained detector dogs to keep the snakes out of the island's cargo flow. The United States Geological Survey also has dogs capable of detecting snakes in forested environments around the region's islands.

Now answer this question: What has the U.S Department of Agriculture done to help watch for the snakes?

Output: has trained detector dogs to keep the snakes out of the island's cargo flow

Input: Article: The waterwheel appeared in Chinese records during the Han. As mentioned by Huan Tan in about 20 AD, they were used to turn gears that lifted iron trip hammers, and were used in pounding, threshing and polishing grain. However, there is no sufficient evidence for the watermill in China until about the 5th century. The Nanyang Commandery Administrator Du Shi (d. 38 AD) created a waterwheel-powered reciprocator that worked the bellows for the smelting of iron. Waterwheels were also used to power chain pumps that lifted water to raised irrigation ditches. The chain pump was first mentioned in China by the philosopher Wang Chong in his 1st-century-AD Balanced Discourse.

Now answer this question: During what century is it likely that the watermill made an appearance in China?

Output: about the 5th century

Input: Article: It had been found that the proportion of non-repetitive DNA can vary a lot between species. Some E. coli as prokaryotes only have non-repetitive DNA, lower eukaryotes such as C. elegans and fruit fly, still possess more non-repetitive DNA than repetitive DNA. Higher eukaryotes tend to have more repetitive DNA than non-repetitive ones. In some plants and amphibians, the proportion of non-repetitive DNA is no more than 20%, becoming a minority component.

Now answer this question: What is an example of an organism which does not contain any repetitive DNA?

Output:
E. coli