Answer:
I am an object which is used in baseball during the day I can't be seen at all
I am so delicate that even mentioning me breaks me. What am I?
By myself, I'm practically nothing. Worthless as a leader, but when I follow a group, their strength increases tenfold. What am I?
I am not alive but I grow I don't have lungs but I need air I don't have a mouth but water kills me. What am I?
You cannot keep me until you have given me. What am I?
What never gets any wetter no matter how hard it rains?