QUES: The surface bedrock under the Miami area is called Miami oolite or Miami limestone. This bedrock is covered by a thin layer of soil, and is no more than 50 feet (15 m) thick. Miami limestone formed as the result of the drastic changes in sea level associated with recent glaciations or ice ages. Beginning some 130,000 years ago the Sangamonian Stage raised sea levels to approximately 25 feet (8 m) above the current level. All of southern Florida was covered by a shallow sea. Several parallel lines of reef formed along the edge of the submerged Florida plateau, stretching from the present Miami area to what is now the Dry Tortugas. The area behind this reef line was in effect a large lagoon, and the Miami limestone formed throughout the area from the deposition of oolites and the shells of bryozoans. Starting about 100,000 years ago the Wisconsin glaciation began lowering sea levels, exposing the floor of the lagoon. By 15,000 years ago, the sea level had dropped to 300 to 350 feet (90 to 110 m) below the contemporary level. The sea level rose quickly after that, stabilizing at the current level about 4000 years ago, leaving the mainland of South Florida just above sea level.

What event caused sea levels to decrease approximately 100,000 years ago?
What is the answer?
ANS: Wisconsin glaciation
QUES: In 1821, Mexico won its independence from Spain, and San Diego became part of the Mexican territory of Alta California. In 1822, Mexico began attempting to extend its authority over the coastal territory of Alta California. The fort on Presidio Hill was gradually abandoned, while the town of San Diego grew up on the level land below Presidio Hill. The Mission was secularized by the Mexican government in 1833, and most of the Mission lands were sold to wealthy Californio settlers. The 432 residents of the town petitioned the governor to form a pueblo, and Juan María Osuna was elected the first alcalde ("municipal magistrate"), defeating Pío Pico in the vote. (See, List of pre-statehood mayors of San Diego.) However, San Diego had been losing population throughout the 1830s and in 1838 the town lost its pueblo status because its size dropped to an estimated 100 to 150 residents. Beyond town Mexican land grants expanded the number of California ranchos that modestly added to the local economy.

Who was in the running for the first alcalde position, but was defeated in the election?
What is the answer?
ANS: Pío Pico
QUES: The most important existing communal shelters were the London Underground stations. Although many civilians had used them as such during the First World War, the government in 1939 refused to allow the stations to be used as shelters so as not to interfere with commuter and troop travel, and the fears that occupants might refuse to leave. Underground officials were ordered to lock station entrances during raids; but by the second week of heavy bombing the government relented and ordered the stations to be opened. Each day orderly lines of people queued until 4 pm, when they were allowed to enter the stations. In mid-September 1940 about 150,000 a night slept in the Underground, although by the winter and spring months the numbers had declined to 100,000 or less. Noises of battle were muffled and sleep was easier in the deepest stations, but many were killed from direct hits on several stations.

In 1940 how many people were sleeping in the Underground stations?
What is the answer?
ANS:
150,000 a night