Problem: Cardinal (Catholicism):

The Dean of the College of Cardinals, or Cardinal-dean, is the primus inter pares of the College of Cardinals, elected by the cardinal bishops holding suburbicarian sees from among their own number, an election, however, that must be approved by the Pope. Formerly the position of dean belonged by right to the longest-serving of the cardinal bishops.

Who does not need the approval of the Pope?
---
A: unanswerable

Problem: Sahara:

By 6000 BCE predynastic Egyptians in the southwestern corner of Egypt were herding cattle and constructing large buildings. Subsistence in organized and permanent settlements in predynastic Egypt by the middle of the 6th millennium BCE centered predominantly on cereal and animal agriculture: cattle, goats, pigs and sheep. Metal objects replaced prior ones of stone. Tanning of animal skins, pottery and weaving were commonplace in this era also. There are indications of seasonal or only temporary occupation of the Al Fayyum in the 6th millennium BCE, with food activities centering on fishing, hunting and food-gathering. Stone arrowheads, knives and scrapers from the era are commonly found. Burial items included pottery, jewelry, farming and hunting equipment, and assorted foods including dried meat and fruit. Burial in desert environments appears to enhance Egyptian preservation rites, and dead were buried facing due west.

By what time period were the Egyptians constructing large buildings?
---
A: 6000 BCE

Problem: Black people:

Because of the acceptance of miscegenation, Brazil has avoided the binary polarization of society into black and white. In addition, it abolished slavery without a civil war. The bitter and sometimes violent racial tensions that have divided the US are notably absent in Brazil. According to the 2010 census, 6.7% of Brazilians said they were black, compared with 6.2% in 2000, and 43.1% said they were racially mixed, up from 38.5%. In 2010, Elio Ferreira de Araujo, Brazil's minister for racial equality, attributed the increases to growing pride among his country's black and indigenous communities.

What is happened in the US that did not happen in Brazil when slavery ended?
---
A: civil war

Problem: Molotov%E2%80%93Ribbentrop Pact:

In an effort to demonstrate peaceful intentions toward Germany, on 13 April 1941, the Soviets signed a neutrality pact with Axis power Japan. While Stalin had little faith in Japan's commitment to neutrality, he felt that the pact was important for its political symbolism, to reinforce a public affection for Germany. Stalin felt that there was a growing split in German circles about whether Germany should initiate a war with the Soviet Union. Stalin did not know that Hitler had been secretly discussing an invasion of the Soviet Union since summer 1940, and that Hitler had ordered his military in late 1940 to prepare for war in the east regardless of the parties' talks of a potential Soviet entry as a fourth Axis Power.

Who did the Soviet Union disagree to remain neutral with when they signed a treaty on the 13th of April?
---
A:
unanswerable