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To the north of Africa the Tethys Sea continued to narrow. Broad shallow seas advanced across central North America (the Western Interior Seaway) and Europe, then receded late in the period, leaving thick marine deposits sandwiched between coal beds. At the peak of the Cretaceous transgression, one-third of Earth's present land area was submerged. The Cretaceous is justly famous for its chalk; indeed, more chalk formed in the Cretaceous than in any other period in the Phanerozoic. Mid-ocean ridge activity—or rather, the circulation of seawater through the enlarged ridges—enriched the oceans in calcium; this made the oceans more saturated, as well as increased the bioavailability of the element for calcareous nanoplankton. These widespread carbonates and other sedimentary deposits make the Cretaceous rock record especially fine. Famous formations from North America include the rich marine fossils of Kansas's Smoky Hill Chalk Member and the terrestrial fauna of the late Cretaceous Hell Creek Formation. Other important Cretaceous exposures occur in Europe and China. In the area that is now India, massive lava beds called the Deccan Traps were laid down in the very late Cretaceous and early Paleocene.
What sea north of Africa coninued to broaden?
A: unanswerable

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Vernacular architecture became increasingly ornamental. House builders could use current architectural design in their work by combining features found in pattern books and architectural journals.
What type of design did these texts allow the builders to incorporate?
A: current architectural design

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Mali (i/ˈmɑːli/; French: [maˈli]), officially the Republic of Mali (French: République du Mali), is a landlocked country in West Africa. Mali is the eighth-largest country in Africa, with an area of just over 1,240,000 square kilometres (480,000 sq mi). The population of Mali is 14.5 million. Its capital is Bamako. Mali consists of eight regions and its borders on the north reach deep into the middle of the Sahara Desert, while the country's southern part, where the majority of inhabitants live, features the Niger and Senegal rivers. The country's economy centers on agriculture and fishing. Some of Mali's prominent natural resources include gold, being the third largest producer of gold in the African continent, and salt. About half the population lives below the international poverty line of $1.25 (U.S.) a day. A majority of the population (55%) are non-denominational Muslims.
What is basal agriculture in deep-sea fishing?
A: unanswerable

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Additionally, genes can have regulatory regions many kilobases upstream or downstream of the open reading frame. These act by binding to transcription factors which then cause the DNA to loop so that the regulatory sequence (and bound transcription factor) become close to the RNA polymerase binding site. For example, enhancers increase transcription by binding an activator protein which then helps to recruit the RNA polymerase to the promoter; conversely silencers bind repressor proteins and make the DNA less available for RNA polymerase.
How do regulatory regions act?
A:
by binding to transcription factors