Problem: Tehran is the country's capital and largest city, as well as its leading cultural and economic center. Iran is a major regional and middle power, exerting considerable influence in international energy security and the world economy through its large reserves of fossil fuels, which include the largest natural gas supply in the world and the fourth-largest proven oil reserves. Iran's rich cultural legacy is reflected in part by its 19 UNESCO World Heritage Sites, the fourth-largest number in Asia and 12th-largest in the world.
How does Iran effect the world economy and international energy markets?
The answer is the following: through its large reserves of fossil fuels

Problem: The Ismailis differ from Twelvers because they had living imams for centuries after the last Twelver Imam went into concealment. They followed Isma'il ibn Jafar, elder brother of Musa al-Kadhim, as the rightful Imam after his father Ja'far al-Sadiq. The Ismailis believe that whether Imam Ismail did or did not die before Imam Ja'far, he had passed on the mantle of the imamate to his son Muḥammad ibn Ismail as the next imam. Thus, their line of imams is as follows (the years of their individual imamats during the Common Era are given in brackets):
How do Ismailis differ from Twelvers?
The answer is the following: living imams

Problem: As in the other Western Romance languages, the main plural expression is the suffix -s, which may create morphological alternations similar to the ones found in gender inflection, albeit more rarely. The most important one is the addition of -o- before certain consonant groups, a phonetic phenomenon that does not affect feminine forms: el pols/els polsos ("the pulse"/"the pulses") vs. la pols/les pols ("the dust"/"the dusts").
What is an important plural alternation?
The answer is the following: addition of -o-

Problem: Proponents of affirmative action recognize that the policy is inherently unequal; however, minding the inescapable fact that historic inequalities exist in America, they believe the policy is much more fair than one in which these circumstances are not taken into account. Furthermore, those in favor of affirmative action see it as an effort towards inclusion rather than a discriminatory practice. "Job discrimination is grounded in prejudice and exclusion, whereas affirmative action is an effort to overcome prejudicial treatment through inclusion. The most effective way to cure society of exclusionary practices is to make special efforts at inclusion, which is exactly what affirmative action does."
What does affirmative action supposedly aim to do?
The answer is the following:
overcome prejudicial treatment through inclusion