Some Interesting confusions

1. Can you cry under water?
   
   
2. Do fish ever get thirsty?
   
   
3. Why dont birds fall out of trees, when they sleep?
   
   
4. What do you call a male lady bird?
   
   
5. Why is it called building, when it is already built?
   
   
6. When they say dog food is new n improved in taste. Who tastes it?