Problem: On September 30, 1989, thousands of Belorussians, denouncing local leaders, marched through Minsk to demand additional cleanup of the 1986 Chernobyl disaster site in Ukraine. Up to 15,000 protesters wearing armbands bearing radioactivity symbols and carrying the banned red-and-white Belorussian national flag filed through torrential rain in defiance of a ban by local authorities. Later, they gathered in the city center near the government's headquarters, where speakers demanded resignation of Yefrem Sokolov, the republic's Communist Party leader, and called for the evacuation of half a million people from the contaminated zones.
Where did the Chernobyl Disaster occur?
The answer is the following: Ukraine

Problem: Portugal’s national energy transmission company, Redes Energéticas Nacionais (REN), uses sophisticated modeling to predict weather, especially wind patterns, and computer programs to calculate energy from the various renewable-energy plants. Before the solar/wind revolution, Portugal had generated electricity from hydropower plants on its rivers for decades. New programs combine wind and water: wind-driven turbines pump water uphill at night, the most blustery period; then the water flows downhill by day, generating electricity, when consumer demand is highest. Portugal’s distribution system is also now a two-way street. Instead of just delivering electricity, it draws electricity from even the smallest generators, like rooftop solar panels. The government aggressively encouraged such contributions by setting a premium price for those who buy rooftop-generated solar electricity.
How did the Portuguese government encourage rooftop solar panels?
The answer is the following: setting a premium price

Problem: In 2008, a BeiDou-1 ground terminal cost around CN¥20,000RMB (US$2,929), almost 10 times the price of a contemporary GPS terminal. The price of the terminals was explained as being due to the cost of imported microchips. At the China High-Tech Fair ELEXCON of November 2009 in Shenzhen, a BeiDou terminal priced at CN¥3,000RMB was presented.
Why is a BeiDou-1 ground terminal so expensive?
The answer is the following: due to the cost of imported microchips

Problem: In early 1758, Frederick launched an invasion of Moravia, and laid siege to Olmütz (now Olomouc, Czech Republic). Following an Austrian victory at the Battle of Domstadtl that wiped out a supply convoy destined for Olmütz, Frederick broke off the siege and withdrew from Moravia. It marked the end of his final attempt to launch a major invasion of Austrian territory. East Prussia had been occupied by Russian forces over the winter and would remain under their control until 1762, although Frederick did not see the Russians as an immediate threat and instead entertained hopes of first fighting a decisive battle against Austria that would knock them out of the war.
What turned the battle for Olmutz against Frederick?
The answer is the following:
Austrian victory at the Battle of Domstadtl that wiped out a supply convoy destined for Olmütz,