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.

In 1872, Russian Alexander Lodygin invented an incandescent light bulb and obtained a Russian patent in 1874. He used as a burner two carbon rods of diminished section in a glass receiver, hermetically sealed, and filled with nitrogen, electrically arranged so that the current could be passed to the second carbon when the first had been consumed. Later he lived in the USA, changed his name to Alexander de Lodyguine and applied and obtained patents for incandescent lamps having chromium, iridium, rhodium, ruthenium, osmium, molybdenum and tungsten filaments, and a bulb using a molybdenum filament was demonstrated at the world fair of 1900 in Paris.
Who patented an incandescent light bulb in Russia in 1874?

According to China daily. Fifteen years after the satellite system was launched, it is now generating $31.5 billion for major companies such as China Aerospace Science and Industry Corp, AutoNavi Holdings Ltd, and China North Industries Group Corp.
How long ago was the BeiDou Satellite System first launched?

Agriculture accounted for less than 20% of both net material product and total employment before the dissolution of the Soviet Union in 1991. After independence, the importance of agriculture in the economy increased markedly, its share at the end of the 1990s rising to more than 30% of GDP and more than 40% of total employment. This increase in the importance of agriculture was attributable to food security needs of the population in the face of uncertainty during the first phases of transition and the collapse of the non-agricultural sectors of the economy in the early 1990s. As the economic situation stabilized and growth resumed, the share of agriculture in GDP dropped to slightly over 20% (2006 data), although the share of agriculture in employment remained more than 40%.

Was agriculture more important before or after Armenia left the Soviet Union?