Problem: Nosopsyllus fasciatus, the northern rat flea, is a species of flea found on domestic rats and house mice. Northern rat fleas are external parasites, living by hematophagy off the blood of rodents. It is the most widely spread of its genus, having originated in Europe, but has been transported to temperate regions all over the world.

Based on the paragraph above can we conclude that "The rat flea are always found on rodents but not always rats."?

A: It's impossible to say

Problem: Dave Ward, born 12 July 1959, is a British Trade Unionist and General Secretary of the Communication Workers' Union (CWU), which was formed through the merger of the Union of Communication Workers and the National Communications Union in 1995. The CWU is the largest Trade Union in the United Kingdom for people working in the Postal and Telecommunications industry with over 200,000 members.

Based on the paragraph above can we conclude that "Dave Ward was paid more after the merger."?

A: It's impossible to say

Problem: Valentin Vitalyevich Lebedev (Russian: ; born April 14, 1942 in Moscow) was a Soviet cosmonaut who made two flights into space. His stay aboard the Space Station Salyut 7 with Anatoly Berezovoy in 1982, which lasted 211 days, was recorded in the Guinness Book of Records.

Based on the paragraph above can we conclude that "Valentin has never been to russia before"?

A:
No