Question: In the mid-1950s, Frank Burnet, inspired by a suggestion made by Niels Jerne, formulated the clonal selection theory (CST) of immunity. On the basis of CST, Burnet developed a theory of how an immune response is triggered according to the self/nonself distinction: "self" constituents (constituents of the body) do not trigger destructive immune responses, while "nonself" entities (e.g., pathogens, an allograft) trigger a destructive immune response. The theory was later modified to reflect new discoveries regarding histocompatibility or the complex "two-signal" activation of T cells. The self/nonself theory of immunity and the self/nonself vocabulary have been criticized, but remain very influential.
Is there an answer to this question: What property of T cells caused modification of CST?

Answer: the complex "two-signal" activation

Question: In mid-2015 the government of Zhejiang recognised folk religion as "civil religion" beginning the registration of more than twenty thousand folk religious associations. Buddhism has an important presence since its arrival in Zhejiang 1,800 years ago.
Is there an answer to this question: What year did the government of Zhejiang reject folk religion as 'civil religion'?

Answer: unanswerable

Question: The city is represented in the National Football League by the New York Giants and the New York Jets, although both teams play their home games at MetLife Stadium in nearby East Rutherford, New Jersey, which hosted Super Bowl XLVIII in 2014.
Is there an answer to this question: In what year did a Super Bowl occur at MetLife Stadium?

Answer: 2014

Question: A peninsula between the Gulf of Mexico, the Atlantic Ocean, and the Straits of Florida, it has the longest coastline in the contiguous United States, approximately 1,350 miles (2,170 km), and is the only state that borders both the Gulf of Mexico and the Atlantic Ocean. Much of the state is at or near sea level and is characterized by sedimentary soil. The climate varies from subtropical in the north to tropical in the south. The American alligator, American crocodile, Florida panther, and manatee can be found in the Everglades National Park.
Is there an answer to this question: What is the length of the shortest Contiguous Coastline in the US?

Answer:
unanswerable