During the years 1940-1955, the rate of decline in the U.S. death rate accelerated from 2% per year to 8% per year, then returned to the historical rate of 2% per year. The dramatic decline in the immediate post-war years has been attributed to the rapid development of new treatments and vaccines for infectious disease that occurred during these years. Vaccine development continued to accelerate, with the most notable achievement of the period being Jonas Salk's 1954 development of the polio vaccine under the funding of the non-profit National Foundation for Infantile Paralysis. The vaccine process was never patented, but was instead given to pharmaceutical companies to manufacture as a low-cost generic. In 1960 Maurice Hilleman of Merck Sharp & Dohme identified the SV40 virus, which was later shown to cause tumors in many mammalian species. It was later determined that SV40 was present as a contaminant in polio vaccine lots that had been administered to 90% of the children in the United States. The contamination appears to have originated both in the original cell stock and in monkey tissue used for production. In 2004 the United States Cancer Institute announced that it had concluded that SV40 is not associated with cancer in people.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What was a complication of the SV40 virus?
Ah, so.. cause tumors

As the center of the empire, early-Ming Nanjing had worldwide connections. It was home of the admiral Zheng He, who went to sail the Pacific and Indian Oceans, and it was visited by foreign dignitaries, such as a king from Borneo (Boni 渤泥), who died during his visit to China in 1408. The Tomb of the King of Boni, with a spirit way and a tortoise stele, was discovered in Yuhuatai District (south of the walled city) in 1958, and has been restored.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What Admiral called Nanjing his home?
Ah, so.. admiral Zheng He

The city had a population of 1,307,402 according to the 2010 census, distributed over a land area of 372.1 square miles (963.7 km2). The urban area of San Diego extends beyond the administrative city limits and had a total population of 2,956,746, making it the third-largest urban area in the state, after that of the Los Angeles metropolitan area and San Francisco metropolitan area. They, along with the Riverside–San Bernardino, form those metropolitan areas in California larger than the San Diego metropolitan area, with a total population of 3,095,313 at the 2010 census.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): In the top five largest urban areas in California, where does San Diego rank?
Ah, so..
third-largest