Answer:
I am an object which is used in baseball. During the day I can't be seen at all. What am I?
I am full of holes but still hold water. What am I?
What has four wheels and flies?
I can be swallowed But I can also swallow you.
I am a protector. I sit on a bridge. One person can see right through me, while others wonder what I hide. What am I?
Though not a plant, has leaves. Though not a beast, has spine. Though many wouldn't need this thing, It's more valuable than wine.