Funny riddles and puzzles

What month of the year has 28 days?(you can choose more than 1 options)

What has many keys but can’t open a single lock?

I am a mother's child and a father's child..but nobody's son.Who am I?

Kartik was 13 years old in 1870..and 8 years old in 1875..How is it possible?

Which is the ten letter word which starts with gas?

What flies when it's born,lies when it's alive and run when it's dead?

I start with M..end with X,and have a never ending amount of letters.What am I?

In roman numerals,how many hours in a day?

I'm a 7 letter word.I become longer when my third letter is removed.Who am I?

A city where we can't even enter.Who am I?(all letters should be in small)

(a)