This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.

Around 2.5 million years ago (ending 11,600 years ago) was the geological period of the Ice Ages. Since approximately 600,000 years ago, six major Ice Ages have occurred, in which sea level dropped 120 m (390 ft) and much of the continental margins became exposed. In the Early Pleistocene, the Rhine followed a course to the northwest, through the present North Sea. During the so-called Anglian glaciation (~450,000 yr BP, marine oxygen isotope stage 12), the northern part of the present North Sea was blocked by the ice and a large lake developed, that overflowed through the English Channel. This caused the Rhine's course to be diverted through the English Channel. Since then, during glacial times, the river mouth was located offshore of Brest, France and rivers, like the Thames and the Seine, became tributaries to the Rhine. During interglacials, when sea level rose to approximately the present level, the Rhine built deltas, in what is now the Netherlands.
What period was 2.5 million years ago?

Transport in the Republic of the Congo includes land, air and water transportation. The country's rail system was built by forced laborers during the 1930s and largely remains in operation. There are also over 1000 km of paved roads and two major international airports (Maya-Maya Airport and Pointe Noire Airport) which have flights to Paris and many African cities. The country also has a large port on the Atlantic Ocean at Pointe-Noire and others along the Congo River at Brazzaville and Impfondo.
What forms of transport are available in the Congo?

Rapid increases in a number of commodity prices followed the collapse in the housing bubble. The price of oil nearly tripled from $50 to $147 from early 2007 to 2008, before plunging as the financial crisis began to take hold in late 2008. Experts debate the causes, with some attributing it to speculative flow of money from housing and other investments into commodities, some to monetary policy, and some to the increasing feeling of raw materials scarcity in a fast-growing world, leading to long positions taken on those markets, such as Chinese increasing presence in Africa. An increase in oil prices tends to divert a larger share of consumer spending into gasoline, which creates downward pressure on economic growth in oil importing countries, as wealth flows to oil-producing states. A pattern of spiking instability in the price of oil over the decade leading up to the price high of 2008 has been recently identified. The destabilizing effects of this price variance has been proposed as a contributory factor in the financial crisis.

Following the collapse in the housing bubble, what happened to a number of commodity prices?