Good Riddles

Question: The more of me you have, the longer your life.
The more of me you have, the less you have left.

What am I?

Question: Light hides me and darkness kills me.

What am I?

Question: A claustrophobic person gets on a train. The train enters a tunnel just as it is leaving the station.

Where is the best place for him to sit?

Question: The first is a sign of something good,
the second says whereto;
the third is vulgar and mean,
the fourth is bound by a ring;
the fifth is the noble one.
Together they all drum.

What are they?

Question: I am the black child of a white father, a wingless bird, flying even to the clouds of heaven.
I give birth to tears of mourning in pupils that meet me, even though there is no cause for grief, and at once on my birth I am dissolved into air.

What am I?