The American bison is a large bovid which inhabited much of western North America prior to the 1800s, living on the prairies in large herds. However, the vast herds of bison attracted market hunters, who killed dozens of bison for their hides only, leaving the rest to rot. Thousands of these hunters quickly eliminated the bison herds, bringing the population from several million in the early 1800s to a few hundred by the 1880s. Conservation efforts have allowed the population to increase, but the bison remains near-threatened.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What areas of the US were settled first in 1880?
Ah, so.. unanswerable

Attestations of Old Dutch sentences are extremely rare. The oldest one first recorded has been found in the Salic law. From this Frankish document written around 510 the oldest sentence has been identified as Dutch: Maltho thi afrio lito (I say to you, I free you, serf) used to free a serf. Another old fragment of Dutch is Visc flot aftar themo uuatare (A fish was swimming in the water). The oldest conserved larger Dutch text is the Utrecht baptismal vow (776-800) starting with Forsachistu diobolae [...] ec forsacho diabolae (Do you forsake the devil? [...] I forsake the devil). Probably the most famous sentence Hebban olla vogala nestas hagunnan, hinase hic enda tu, wat unbidan we nu (All birds have started making nests, except me and you, what are we waiting for), is dated around the year 1100, written by a Flemish monk in a convent in Rochester, England.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What historically significant Dutch document begins with the phrase "Forsachistu diobolae"?
Ah, so.. the Utrecht baptismal vow

The Constitution provides that "a regular Statement and Account of the Receipts and Expenditures of all public Money shall be published from time to time". That provision of the Constitution is made specific by Section 331 of Title 31 of the United States Code. The sums of money reported in the "Statements" are currently being expressed in U.S. dollars (for example, see the 2009 Financial Report of the United States Government). The U.S. dollar may therefore be described as the unit of account of the United States.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What is the unit of account of the United States?
Ah, so..
U.S. dollar