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The PermianTriassic extinction event, which was a prolonged event due to the accumulation of several extinction pulses, ended the dominance of the carnivores among the therapsids. In the early Triassic, all the medium to large land carnivore niches were taken over by archosaurs which, over an extended period of time (35 million years), came to include the crocodylomorphs, the pterosaurs, and the dinosaurs. By the Jurassic, the dinosaurs had come to dominate the large terrestrial herbivore niches as well.
During which time period did archosaurs begin to take over as the dominant carnivore?
A: Triassic

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On November 13, 1988, approximately 10,000 people attended an officially sanctioned meeting organized by the cultural heritage organization Spadschyna, the Kyiv University student club Hromada, and the environmental groups Zelenyi Svit ("Green World") and Noosfera, to focus on ecological issues. From November 1418, 15 Ukrainian activists were among the 100 human-, national- and religious-rights advocates invited to discuss human rights with Soviet officials and a visiting delegation of the U.S. Commission on Security and Cooperation in Europe (also known as the Helsinki Commission). On December 10, hundreds gathered in Kiev to observe International Human Rights Day at a rally organized by the Democratic Union. The unauthorized gathering resulted in the detention of local activists.
What sort of issues were Zenlenyi Svit and Noosfera concerned with?
A: ecological

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"4 Minutes" was released as the album's lead single and peaked at number three on the Billboard Hot 100. It was Madonna's 37th top-ten hit on the chartit pushed Madonna past Elvis Presley as the artist with the most top-ten hits. In the UK she retained her record for the most number-one singles for a female artist; "4 Minutes" becoming her thirteenth. At the 23rd Japan Gold Disc Awards, Madonna received her fifth Artist of the Year trophy from Recording Industry Association of Japan, the most for any artist. To further promote the album, Madonna embarked on the Sticky & Sweet Tour; her first major venture with Live Nation. With a gross of $280 million, it became the highest-grossing tour by a solo artist then, surpassing the previous record Madonna set with the Confessions Tour; it was later surpassed by Roger Waters' The Wall Live. It was extended to the next year, adding new European dates, and after it ended, the total gross was $408 million.
4 minutes became Madonna's which number one single in the UK?
A: thirteenth

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At the time structures such as Lie algebras and hyperbolic quaternions drew attention to the need to expand algebraic structures beyond the associatively multiplicative class. In a review Alexander Macfarlane wrote: "The main idea of the work is not unification of the several methods, nor generalization of ordinary algebra so as to include them, but rather the comparative study of their several structures." In a separate review, G. B. Mathews wrote, "It possesses a unity of design which is really remarkable, considering the variety of its themes."
Reviewer Alexander Macfarlane believed that the main idea of the work is a comparative study of what?
A:
several structures