In the United States, 25 Hz, a once-common industrial power frequency is used on Amtrak's 25 Hz traction power system at 12 kV on the Northeast Corridor between Washington, D.C. and New York City and on the Keystone Corridor between Harrisburg, Pennsylvania and Philadelphia. SEPTA's 25 Hz traction power system uses the same 12 kV voltage on the catenary in Northeast Philadelphia. This allows for the trains to operate on both the Amtrak and SEPTA power systems. Apart from having an identical catenary voltage, the power distribution systems of Amtrak and SEPTA are very different. The Amtrak power distribution system has a 138 kV transmission network that provides power to substations which then transform the voltage to 12 kV to feed the catenary system. The SEPTA power distribution system uses a 2:1 ratio autotransformer system, with the catenary fed at 12 kV and a return feeder wire fed at 24 kV. The New York, New Haven and Hartford Railroad used an 11 kV system between New York City and New Haven, Connecticut which was converted to 12.5 kV 60 Hz in 1987.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What specification is similar for both Amtrak and Septa systems?
Ah, so.. catenary voltage

The Aleutian Islands are still home to the Aleut people's seafaring society, although they were the first Native Alaskans to be exploited by Russians. Western and Southwestern Alaska are home to the Yup'ik, while their cousins the Alutiiq ~ Sugpiaq lived in what is now Southcentral Alaska. The Gwich'in people of the northern Interior region are Athabaskan and primarily known today for their dependence on the caribou within the much-contested Arctic National Wildlife Refuge. The North Slope and Little Diomede Island are occupied by the widespread Inupiat people.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): Which indigenous group is controversially unknown for hunting caribou on protected land?
Ah, so.. unanswerable

A comprehensive school is a state school that does not select its intake on the basis of academic achievement or aptitude. This is in contrast to the selective school system, where admission is restricted on the basis of selection criteria. The term is commonly used in relation to England and Wales, where comprehensive schools were introduced on an experimental basis in the 1940s and became more widespread from 1965. About 90% of British secondary school pupils now attend comprehensive schools. They correspond broadly to the public high school in the United States and Canada and to the German Gesamtschule.[citation needed]
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What kind of school bases its admissions on academic merit?
Ah, so..
unanswerable