I’m tall when I’m young, and I’m short when I’m old. What am I?

I have an eye but still cannot see.

Who am I?

I came first on earth but second on the heaven.
I also came twice in a week but found just once in a year.
I stay away from months but you can find me in February.

What am I?

I am weightless, but you can see me. Put me in a bucket, and I'll make it lighter. What am I?

I am the beginning of the end, and the end of time and space. I am essential to creation, and I surround every place. What am I?

I’m orange, I wear a green hat and I sound like a parrot. What am I?

I have a clock(12-hour format) and both the needles of the clock overlap at 12:00.
After how much time, they will overlap again?

How many sides does a circle have?

Three ants are going up a hill, one behind the other. The last ant then says to the other ants, 'There is an ant behind me!'' How come?

Pronounced as one letter,
And written with three,
Two letters there are,
And two only in me.
I am double, I am single,
I am black blue and grey,
I am read from both ends,
And the same either way.