Misc: What is a group of mares?

Questions

A Pan Am flight, which left London Heathrow bound for New York in December 1998, was blown up by a bomb over a small Scotish town Name the town?

What was Krakatoa?

What type of accident happened at Chernobyl in the USSR in 1986?

In the 1960's, a tranquilizing drug, thought to have no harmful effects, was marketed in Britain and other countries as a therapy for morning sickness, resulting in the birth of hundreds of deformed babies Name the drug?

What are the scientists who study volcanoes called?