Problem: Railway electrification system:

In the former Soviet Union, electric traction eventually became somewhat more energy-efficient than diesel. Partly due to inefficient generation of electricity in the USSR (only 20.8% thermal efficiency in 1950 vs. 36.2% in 1975), in 1950 diesel traction was about twice as energy efficient as electric traction (in terms of net tonne-km of freight per kg of fuel). But as efficiency of electricity generation (and thus of electric traction) improved, by about 1965 electric railways became more efficient than diesel. After the mid 1970s electrics used about 25% less fuel per ton-km. However diesels were mainly used on single track lines with a fair amount of traffic so that the lower fuel consumption of electrics may be in part due to better operating conditions on electrified lines (such as double tracking) rather than inherent energy efficiency. Nevertheless, the cost of diesel fuel was about 1.5 times more (per unit of heat energy content) than that of the fuel used in electric power plants (that generated electricity), thus making electric railways even more energy-cost effective.

What type of trains became more energy-efficient in the former Soviet Union?
---
A: electric

Problem: Tennessee:

The Tennessee income tax does not apply to salaries and wages, but most income from stock, bonds and notes receivable is taxable. All taxable dividends and interest which exceed the $1,250 single exemption or the $2,500 joint exemption are taxable at the rate of 6%. The state's sales and use tax rate for most items is 7%. Food is taxed at a lower rate of 5.25%, but candy, dietary supplements and prepared food are taxed at the full 7% rate. Local sales taxes are collected in most jurisdictions, at rates varying from 1.5% to 2.75%, bringing the total sales tax to between 8.5% and 9.75%, one of the highest levels in the nation. Intangible property is assessed on the shares of stock of stockholders of any loan company, investment company, insurance company or for-profit cemetery companies. The assessment ratio is 40% of the value multiplied by the tax rate for the jurisdiction. Tennessee imposes an inheritance tax on decedents' estates that exceed maximum single exemption limits ($1,000,000 for deaths in 2006 and thereafter).

At what rate is Tennessee state sales and use tax usually applied?
---
A: 7%

Problem: House music:

In a 1986 interview, Rocky Jones, the former club DJ who ran the D.J. International record label, doesn't mention Importes Etc., Frankie Knuckles, or the Warehouse by name, but agrees that "house" was a regional catch-all term for dance music, and that it was once synonymous with older disco music.

For what kind of music was Jones a regional catch-all term?
---
A: unanswerable

Problem: Endangered Species Act:

Growing scientific recognition of the role of private lands for endangered species recovery and the landmark 1981 court decision in Palila v. Hawaii Department of Land and Natural Resources both contributed to making Habitat Conservation Plans/ Incidental Take Permits "a major force for wildlife conservation and a major headache to the development community", wrote Robert D.Thornton in the 1991 Environmental Law article, Searching for Consensus and Predictability: Habitat Conservation Planning under the Endangered Species Act of 1973.

When did private lands start to have more recognition?
---
A:
unanswerable