Best riddles with simple answers

cleanlogicmysterywho am I

I am a 5 letter word. Take away the first letter and I am a country's name. Take away the first two letters and I become the opposite of the 5 letter word. Who am I?
Woman, oman, man.
66.60 %
425 votes
what am Itricky

While I am in air, I am not in oxygen. I am also in water, but not in hydrogen. I am necessary in all animals, but you won't find me in the zoo. Look in all brains and you'll find me there too. What am I?
The Letter A.
66.53 %
200 votes