What is the purpose of using a heart-lung machine during certain cardiac procedures?

What is the name of the balloon embolectomy catheter? 

The filament in an x-ray tube is primarily made of which material?

Which American president was the first to send military advisors and financial aid to Vietnam?

When Herbert Hoover took office in March 1929, the U.S. economy

Alfred Thayer Mahan urged the United States to invade Cuba on moral grounds in supporting their cause for freedom

I was the music festival of the decade (maybe the century), a major event in the Hippie counterculture–LSD and other drugs optional. What was                              ?

I was a Soviet leader who promoted the political reforms of perestroikaand glasnost. Who was                            ?

My pledge of “No New Taxes” doomed me as a one-term president. Who was                               ?

Women finally got the vote with which constitutional amendment and when?