What do you call a fish without an eye?

In the given figure, move three matchsticks so that the resulting figure contains two rectangles.

I have a hole in my back and legs I lack.
I live where I can’t breathe and I eat without teeth.
What am I?

You are presented with three boxes. One of them has a red ball inside and the other two have a black ball inside each of them. You are asked to pick up the one with red ball and you pick one. Now, one of the other boxes is opened and it is found to have a black ball.

You are presented with a chance to change your box with the one that is left closed. Will you change your box? Why or why not?

I have an eye but still cannot see.

Who am I?

They are the five precious gems of an everyday sort and all can be found on a Tennis Court. Who are they?

What is black when you buy it, red when you use it, and gray when you throw it away?

Find a 9-digit number, which you will gradually round off starting with units, then tenth, hundred etc., until you get to the last numeral, which you do not round off. The rounding alternates (up, down, up ...). After rounding off 8 times, the final number is 500000000. The original number is commensurable by 6 and 7, all the numbers from 1 to 9 are used, and after rounding four times the sum of the not-rounded numerals equals 24.

I am taken from a mine and shut up in a wooden case, from which I am never released, and yet I am used by almost every person. What am I?

Below rebus represent famous DiCaprio movie. Can you name it?