Logic Riddles

Question: A man wanted to enter and exclusive club, but did not know the password to get in. He waited by the door and listened. The doorman said "Twelve" and the other man said "Six" and was let in. A second member came up and the doorman said "Six" to which the member replied "Three" and was let in. The man went up and the doorman said to him "Ten" the doorman said "Five" but was not let in. Why?

Question: What grows when you take from it?

Question: A rich man suddenly dies from a cut on his finger. The next day, two men appeared and claimed to be his long-lost son. They both fit the description in the will and had all the necessary documents. The family attorney proposed a blood test. One man agreed while the other point blank refused. The one who agreed was arrested for fraud at once. The second man was accepted as the heir. Why?

Question: How do you tell if a snake is venomous or not?

Question: What's small like a mouse but protects like a lion?