Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
Darwin's aims were twofold: to show that species had not been separately created, and to show that natural selection had been the chief agent of change. He knew that his readers were already familiar with the concept of transmutation of species from Vestiges, and his introduction ridicules that work as failing to provide a viable mechanism. Therefore, the first four chapters lay out his case that selection in nature, caused by the struggle for existence, is analogous to the selection of variations under domestication, and that the accumulation of adaptive variations provides a scientifically testable mechanism for evolutionary speciation.
What did heknow his readers were already familiar with from Vestiges?
A: the concept of transmutation of species

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Between 1892, when Harvard and Yale met in one of the first intercollegiate debates, and 1909, the year of the first Triangular Debate of Harvard, Yale, and Princeton, the rhetoric, symbolism, and metaphors used in athletics were used to frame these early debates. Debates were covered on front pages of college newspapers and emphasized in yearbooks, and team members even received the equivalent of athletic letters for their jackets. There even were rallies sending off the debating teams to matches. Yet, the debates never attained the broad appeal that athletics enjoyed. One reason may be that debates do not have a clear winner, as is the case in sports, and that scoring is subjective. In addition, with late 19th-century concerns about the impact of modern life on the human body, athletics offered hope that neither the individual nor the society was coming apart.
In what year was the first debate between Harvard, Yale, and Princeton?
A: 1909

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Many of the limitations of the classic commutator DC motor are due to the need for brushes to press against the commutator. This creates friction. Sparks are created by the brushes making and breaking circuits through the rotor coils as the brushes cross the insulating gaps between commutator sections. Depending on the commutator design, this may include the brushes shorting together adjacent sections and hence coil ends momentarily while crossing the gaps. Furthermore, the inductance of the rotor coils causes the voltage across each to rise when its circuit is opened, increasing the sparking of the brushes. This sparking limits the maximum speed of the machine, as too-rapid sparking will overheat, erode, or even melt the commutator. The current density per unit area of the brushes, in combination with their resistivity, limits the output of the motor. The making and breaking of electric contact also generates electrical noise; sparking generates RFI. Brushes eventually wear out and require replacement, and the commutator itself is subject to wear and maintenance (on larger motors) or replacement (on small motors). The commutator assembly on a large motor is a costly element, requiring precision assembly of many parts. On small motors, the commutator is usually permanently integrated into the rotor, so replacing it usually requires replacing the whole rotor.
What does sparking not limit?
A: unanswerable

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In 1932, Hayek suggested that private investment in the public markets was a better road to wealth and economic co-ordination in Britain than government spending programs, as argued in a letter he co-signed with Lionel Robbins and others in an exchange of letters with John Maynard Keynes in The Times. The nearly decade long deflationary depression in Britain dating from Churchill's decision in 1925 to return Britain to the gold standard at the old pre-war, pre-inflationary par was the public policy backdrop for Hayek's single public engagement with Keynes over British monetary and fiscal policy, otherwise Hayek and Keynes agreed on many theoretical matters, and their economic disagreements were fundamentally theoretical, having to do almost exclusively with the relation of the economics of extending the length of production to the economics of labour inputs.
What did Hayek claim to be better than investing in government spending programs?
A:
private investment in the public markets