The hygiene hypothesis attempts to explain the increased rates of asthma worldwide as a direct and unintended result of reduced exposure, during childhood, to non-pathogenic bacteria and viruses. It has been proposed that the reduced exposure to bacteria and viruses is due, in part, to increased cleanliness and decreased family size in modern societies. Exposure to bacterial endotoxin in early childhood may prevent the development of asthma, but exposure at an older age may provoke bronchoconstriction. Evidence supporting the hygiene hypothesis includes lower rates of asthma on farms and in households with pets.
How does the hygiene hypothesis explain the increase in asthma?
a direct and unintended result of reduced exposure, during childhood, to non-pathogenic bacteria and viruses

In 1941, the General Anaya borough was merged to the Central Department, which was then renamed "Mexico City" (thus reviving the name, but not the autonomous municipality). From 1941 to 1970, the Federal District comprised twelve delegaciones and Mexico City. In 1970 Mexico City was split into four different delegaciones: Cuauhtemoc, Miguel Hidalgo, Venustiano Carranza and Benito Juarez, increasing the number of delegaciones to sixteen. Since then, in a de facto manner, the whole Federal District, whose delegaciones had by then almost formed a single urban area, began to be considered a synonym of Mexico City.
Which boroughs was the Mexico City borough split into?
Cuauhtemoc, Miguel Hidalgo, Venustiano Carranza and Benito Juarez

In a major split in the ranks of Al Qaeda's organization, the Iraqi franchise, known as Al Qaeda in Iraq covertly invaded Syria and the Levant and began participating in the ongoing Syrian Civil War, gaining enough support and strength to re-invade Iraq's western provinces under the name of the Islamic State of Iraq and the Levant (ISIS/ISIL), taking over much of the country in a blitzkrieg-like action and combining the Iraq insurgency and Syrian Civil War into a single conflict. Due to their extreme brutality and a complete change in their overall ideology, Al Qaeda's core organization in Central Asia eventually denounced ISIS and directed their affiliates to cut off all ties with this organization. Many analysts[who?] believe that because of this schism, Al Qaeda and ISIL are now in a competition to retain the title of the world's most powerful terrorist organization.
What relationship do Al Qaeda and ISIS now have?
competition