QUES: Hunter-gatherer societies manifest significant variability, depending on climate zone/life zone, available technology and societal structure. Archaeologists examine hunter-gatherer tool kits to measure variability across different groups. Collard et al. (2005) found temperature to be the only statistically significant factor to impact hunter-gatherer tool kits. Using temperature as a proxy for risk, Collard et al.'s results suggest that environments with extreme temperatures pose a threat to hunter-gatherer systems significant enough to warrant increased variability of tools. These results support Torrence's (1989) theory that risk of failure is indeed the most important factor in determining the structure of hunter-gatherer toolkits.
What is the threat that extreme temperature causes in environment?

ANS: significant

QUES: In response to the demands, in 1987 the Federal District received a greater degree of autonomy, with the elaboration the first Statute of Government (Estatuto de Gobierno), and the creation of an Assembly of Representatives.[citation needed] In the 1990s, this autonomy was further expanded and, starting from 1997, residents can directly elect the head of government of the Federal District and the representatives of a unicameral Legislative Assembly (which succeeded the previous Assembly) by popular vote.
How is the leader of Mexico City now established?

ANS: popular vote

QUES: More commonly, in cases where there are three or more parties, no one party is likely to gain power alone, and parties work with each other to form coalition governments. This has been an emerging trend in the politics of the Republic of Ireland since the 1980s and is almost always the case in Germany on national and state level, and in most constituencies at the communal level. Furthermore, since the forming of the Republic of Iceland there has never been a government not led by a coalition (usually of the Independence Party and one other (often the Social Democratic Alliance). A similar situation exists in the Republic of Ireland; since 1989, no one party has held power on its own. Since then, numerous coalition governments have been formed. These coalitions have been exclusively led by one of either Fianna Fail or Fine Gael. Political change is often easier with a coalition government than in one-party or two-party dominant systems.[dubious discuss] If factions in a two-party system are in fundamental disagreement on policy goals, or even principles, they can be slow to make policy changes, which appears to be the case now in the U.S. with power split between Democrats and Republicans. Still coalition governments struggle, sometimes for years, to change policy and often fail altogether, post World War II France and Italy being prime examples. When one party in a two-party system controls all elective branches, however, policy changes can be both swift and significant. Democrats Woodrow Wilson, Franklin Roosevelt and Lyndon Johnson were beneficiaries of such fortuitous circumstances, as were Republicans as far removed in time as Abraham Lincoln and Ronald Reagan. Barack Obama briefly had such an advantage between 2009 and 2011.
When is political change easier?

ANS: Political change is often easier with a coalition government

QUES: In 2004, a large share of natural gas reserves in Iran were untapped. The addition of new hydroelectric stations and the streamlining of conventional coal and oil-fired stations increased installed capacity to 33,000 megawatts. Of that amount, about 75% was based on natural gas, 18% on oil, and 7% on hydroelectric power. In 2004, Iran opened its first wind-powered and geothermal plants, and the first solar thermal plant is to come online in 2009. Iran is the third country in the world to have developed GTL technology.
When did Iran open its first geothermal plants?

ANS:
2004