Problem: Great Plains:

After 1870, the new railroads across the Plains brought hunters who killed off almost all the bison for their hides. The railroads offered attractive packages of land and transportation to European farmers, who rushed to settle the land. They (and Americans as well) also took advantage of the homestead laws to obtain free farms. Land speculators and local boosters identified many potential towns, and those reached by the railroad had a chance, while the others became ghost towns. In Kansas, for example, nearly 5000 towns were mapped out, but by 1970 only 617 were actually operating. In the mid-20th century, closeness to an interstate exchange determined whether a town would flourish or struggle for business.

How many free farms were doled out overall?
---
A: unanswerable


Problem: In additive color devices such as computer displays and televisions, one of the primary light sources is typically a narrow-spectrum yellowish-green of dominant wavelength ~550 nm; this "green" primary is combined with an orangish-red "red" primary and a purplish-blue "blue" primary to produce any color in between – the RGB color model. A unique green (green appearing neither yellowish nor bluish) is produced on such a device by mixing light from the green primary with some light from the blue primary.
What is unique green's wavelength?
---
Answer: unanswerable


Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
Chanakya, 4th Century BC Indian political philosopher. The Arthashastra provides an account of the science of politics for a wise ruler, policies for foreign affairs and wars, the system of a spy state and surveillance and economic stability of the state. Chanakya quotes several authorities including Bruhaspati, Ushanas, Prachetasa Manu, Parasara, and Ambi, and described himself as a descendant of a lineage of political philosophers, with his father Chanaka being his immediate predecessor. Another influential extant Indian treatise on political philosophy is the Sukra Neeti. An example of a code of law in ancient India is the Manusmṛti or Laws of Manu.
Who was the Indian political philosopher in the fourth century A.D.?
A: unanswerable


Context and question: Historians trace the earliest church labeled Baptist back to 1609 in Amsterdam, with English Separatist John Smyth as its pastor. In accordance with his reading of the New Testament, he rejected baptism of infants and instituted baptism only of believing adults. Baptist practice spread to England, where the General Baptists considered Christ's atonement to extend to all people, while the Particular Baptists believed that it extended only to the elect. In 1638, Roger Williams established the first Baptist congregation in the North American colonies. In the mid-18th century, the First Great Awakening increased Baptist growth in both New England and the South. The Second Great Awakening in the South in the early 19th century increased church membership, as did the preachers' lessening of support for abolition and manumission of slavery, which had been part of the 18th-century teachings. Baptist missionaries have spread their church to every continent.
Where was the earliest Baptist church founded?
Answer: Amsterdam


Question: Often, the migration route of a long-distance migrator bird doesn't follow a straight line between breeding and wintering grounds. Rather, it could follow an hooked or arched line, with detours around geographical barriers. For most land-birds, such barriers could consist in seas, large water bodies or high mountain ranges, because of the lack of stopover or feeding sites, or the lack of thermal columns for broad-winged birds.
Is there an answer to this question: Why do broad winged birds avoid geographical barriers?

Answer: lack of thermal columns


Problem: Portugal:

In 27 BC, Lusitania gained the status of Roman province. Later, a northern province of Lusitania was formed, known as Gallaecia, with capital in Bracara Augusta, today's Braga. There are still many ruins of castros (hill forts) all over modern Portugal and remains of Castro culture. Numerous Roman sites are scattered around present-day Portugal, some urban remains are quite large, like Conímbriga and Mirobriga. The former, beyond being one of the largest Roman settlements in Portugal, is also classified as a National Monument. Conímbriga lies 16 km from Coimbra which by its turn was the ancient Aeminium). The site also has a museum that displays objects found by archaeologists during their excavations.

What are two large Roman sites that still exist today in Portugal?
---
A:
Conímbriga and Mirobriga