Riddle #51

Question: There are 20 birds in a tree. A man comes and shoots one of the birds. How many birds are left?

Question: Surrounded by life , yet life is its biggest enemy. But without life there is no need for it to exist. What is it?

Question: During what month do people sleep the least?

Question: A horse jumps over a castle killing a woman, who is she?

Question: When is 99 more than 100?

Question: What makes a hotel hot even when below zero temperatures?