Can you find out the next digit in the following series ?

0, 0, 1, 3, 2, 6, 3, 9, 4, 12, 5, ?

In the picture that is attached with this question, you can find a square which comprises of four little squares inside it. Consider this square to be made with matchsticks. You have to remove two matchsticks such that only two squares remain instead of five.How will you do it ?

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?

Can you find the thief by just looking at the picture below?

Count the squares in the matchstick puzzle below?

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

You are given four results as below:
1111 = F
2222 = E
3333 = T
Then, can you find out how to code 4444?

You need to pick one entry from pot A and one from pot B to have a perfect match. Can you do it?

You have two bottles of pills marked with labels A and B. The pills are identical. The doctor has asked you to take one A pill and one B pill daily. You cant take more or less than that.

While taking out the pills one day, you took out one pill from A and by mistake took out two from B. You have no idea which pill is which now.

You cant throw away the expensive pills. What will you do now?

Name one eight-letter word with 'kst' in the middle, 'in' the beginning, 'and' at the end.?