TASK DEFINITION: This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.
PROBLEM: However, Lok-Ham Chan, a professor of history at the University of Washington, writes that Changchub Gyaltsen's aims were to recreate the old Tibetan Kingdom that existed during the Chinese Tang dynasty, to build "nationalist sentiment" amongst Tibetans, and to "remove all traces of Mongol suzerainty." Georges Dreyfus, a professor of religion at Williams College, writes that it was Changchub Gyaltsen who adopted the old administrative system of Songtsän Gampo (c. 605–649)—the first leader of the Tibetan Empire to establish Tibet as a strong power—by reinstating its legal code of punishments and administrative units. For example, instead of the 13 governorships established by the Mongol Sakya viceroy, Changchub Gyaltsen divided Central Tibet into districts (dzong) with district heads (dzong dpon) who had to conform to old rituals and wear clothing styles of old Imperial Tibet. Van Praag asserts that Changchub Gyaltsen's ambitions were to "restore to Tibet the glories of its Imperial Age" by reinstating secular administration, promoting "national culture and traditions," and installing a law code that survived into the 20th century.

SOLUTION: Who divided Central Tibet into districts? 

PROBLEM: The evolution of seed plants and later angiosperms appears to be the result of two distinct rounds of whole genome duplication events. These occurred at 319 million years ago and 192 million years ago. Another possible whole genome duplication event at 160 million years ago perhaps created the ancestral line that led to all modern flowering plants. That event was studied by sequencing the genome of an ancient flowering plant, Amborella trichopoda, and directly addresses Darwin's "abominable mystery."

SOLUTION: How many distinct rounds of genome duplication events are suspected in the evolution of seed plants?

PROBLEM: The Islamic Prophet Muhammad carried out a siege against the Banu Qaynuqa tribe known as the Invasion of Banu Qaynuqa in February 624  Muhammad ordered his followers to attack the Banu Qaynuqa Jews for allegedly breaking the treaty known as the Constitution of Medina by pinning the clothes of a Muslim woman, which led to her being stripped naked As a result, a Muslim killed a Jew in retaliation, and the Jews in turn killed the Muslim man. This escalated to a chain of revenge killings, and enmity grew between Muslims and the Banu Qaynuqa, leading to the siege of their fortress.:122 The tribe eventually surrendered to Muhammad, who initially wanted to kill the members of Banu Qaynuqa but ultimately yielded to Abdullah ibn Ubayy's insistence and agreed to expel the Qaynuqa.

SOLUTION:
The Islamic Prophet Muhammad carried out a siege against what tribe in February 624?