Can you convert the number zero(0) into a positive number using just one mathematical operator ?

What is the word or phrase?

What has one eye, but can’t see?

A Detective reviewed the information they had on the case so far.

A lady named 'Caterina' was found shot and they already had a list of suspects - Ankit, Tarun, Harish, Manoj and Manish.
The killer is a fan of challenges him by leaving notes ad various places.
* The first was found in a toilet room.
* The second was found in an art room.
* The third was in a restroom.
* the fourth in an underwater room.
* The fifth at the no-smoking room.

All of the notes read the same thing, 'The clues are where you find the notes.' Yet, nothing was found at any place the notes were.
Detective the genius, immediately solved the case.
Who was the killer?

You may enter, but you may not come in. I have space, but no room. I have keys, but open no lock. What am I?

What part of the chicken has the most feathers?

There are three Athletes (John, Tarun and Harish) and their individual Coaches (Jacob, Meenaxi and Priyanka) standing on the shore.
No Coach trusts their Athlete to be near any other Coach unless they are also with them.
There is a boat that can hold a maximum of two persons.
How can the six people get across the river?

What number should come in place of the question mark below?

Find the number of squares in the below picture

I speak without a mouth, and hear without ears. I have no-body, but I come alive with the wind. What am I?