Toxicological Trivia from February 19, 2014: Poisonous snakes are generally harmless unless they feel threatened. "If safety precautions are maintained, not necessarily pose a threat," says Wolfgang Böhme, curator of reptiles and passionate collector of vipers and snakes, which for 40 years has been dedicated to studying these cold-blooded animals. He never was biting.He have estimated that there are 2,800 varieties of snakes in the world, of which a) Ten percent of them are poisonous; b) Five percent of them are poisonous; c) One percent of them are poisonous. 

Correct Answer a. Read more in Spanish article: Another article on database of poisonous snakes WHO