Given a context passage, generate a question from the passage such that its answer is shortest continous span from the passage.

Q: Leke III Dukagjini (1410--1481), mostly known as Leke Dukagjini, was a mysterious member of the Dukagjini family about whom little is known and who is thought to have been a 15th-century Albanian nobleman.

A: What was the noble family that Lekë Dukagjini was from?
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Q: Treat with Respect The speed with which Man is changing the face of Earth has outstripped all the mighty processes of nature put together. In his haste to supply himself with increasing quantities of Earth's treasures he risks destroying one he greatly needs, his natural surroundings. Some countries set aside unspoiled areas of natural beauty. prefix = st1 /Canadahas the largest system of national parks in the world, 29 in all covering about 13 million hectares, preserving the different landscapes and the plant and animal life. Other countries are restoring areas which have been reduced to waste land by mining. At Broken Hill in Australiadrifting sand from rock crushing turned the area into a desert swept by sand storms. This is now being irrigated, fertilized and planted with grass and trees. In Great Britain quarries and gravel pits are being filled in or made into lakes, industrial wasteland is being turned into playing fields and waste tips into sloping green hills. However Man tries to look after Earth, the fact is that he is using up at a great rate resources, especially fuel resources, which have taken millions of years to accumulate and which he cannot renew. Yet every day the Earth receives a huge supply of energy from the Sun. Man has made several experiments in using solar energy to heat furnaces , cookers, and water-distillers. In space technology, e.g. on satellites, solar cells convert sunlight into electricity. Houses and offices have been designed which are centrally heated by water or air heated by the sunlight. When Man can trap and store this energy, so that he can use it exactly as he needs it, he will have not only an endless supply, but a clean and safe one.

A: According to this selected passage, which energy is considered to be endless, clean and safe?
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Q: Interleukin-6 (IL-6) can activate downstream signaling pathways in lung cancer cells, such as the STAT3 pathway, and is reported to be produced by tumor cells with activating EGFR mutations. We examined IL-6/STAT3 in lung cancer tumor tissues and the effects of siltuximab, a neutralizing antibody to human IL-6, in mouse models of lung cancer. IL-6 and STAT3 activation levels were compared with tumor histology and presence of KRAS mutations in snap-frozen, non-small-cell lung cancer tumors. The effects of siltuximab alone or in combination with erlotinib were examined in mouse xenograft models constructed using three cell line xenograft models and one primary explant mouse model. We examined the influence of cancer-associated fibroblasts (CAFs) on tumor growth and siltuximab effects. IL-6 levels were higher in tumors of squamous cell versus adenocarcinoma histology and were not associated with presence of KRAS mutations. Tyrosine phosphorylation status of STAT3 did not correlate with tumor IL-6 levels. Serine phosphorylation of STAT3 was correlated with KRAS mutation status. Both tumor and stromal cells contributed to total IL-6 within tumors. Siltuximab had minimal effect as a single agent in xenografts with tumor cells alone; however, in models coadministered with CAFs, siltuximab had more potent effects on tumor inhibition. We observed no effects of combined erlotinib and siltuximab. IL-6 is elevated in subsets of human NSCLCs, especially with squamous cell histology. Tumors supported by stromal production of IL-6 seem to be the most vulnerable to tumor growth inhibition by siltuximab.

A:
Which interleukin is blocked by Siltuximab?
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