Can you name an animal whose killing cannot be performed without spilling your own blood?

What does the rebus below mean?

TEN BADTION

Why is 6 afraid of 7?

What do you get if you add 2 to 100 four times?

A man has a barrel filled with oil that weighs 100 pounds, and then he puts something into it. Now the barrel weighs less than 100 pounds. What did he put in the barrel?

I cry without having a voice.
I fly without having wings.
I bite without having teeth.
I whisper without a mouth.

Who am I?

How many minutes are there in Feb 2017?

Note: The shortest answer is the correct answer.

A boy was at a carnival and went to a booth where a man said to the boy, "If I write your exact weight on this piece of paper then you have to give me $50, but if I cannot, I will pay you $50." The boy looked around and saw no scale so he agrees, thinking no matter what the carny writes he'll just say he weighs more or less. In the end the boy ended up paying the man $50. How did the man win the bet?

Name a key which is hardest to turn.

What kind of storm is always in a rush?