Good Riddles

Question: What is often picked but seldom chosen, never walks but can run when frozen?

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: There was once three trees. The first tree did whatever the third tree did, and the third tree did what ever the second one does. What happens if tree number two gets cut down?

Question: Swallowing one is fine.
Swallowing two together is fine.
But Swallow them separately and all shall fall.

What are they?

Question: I fly and never rest. What am I?