What does this rebus means ?

PROG WORKRESS

Always in you, Sometimes on you;

If I surround you, I can kill you.

What am I?

I cry without having a voice.
I fly without having wings.
I bite without having teeth.
I whisper without a mouth.

Who am I?

What happened when the wheel was invented?

Why do Chinese men eat more rice than Japanese men do ?

If Japan and Panama decided to merge into a single country, probably people will name it Japanama.

Can you think of two more such country's unions that could produce similar names like Japanama by overlapping their three letters?

Place a mathematical symbol between the numerals 5 and 9 in such a way that the resulting number is greater than 5 but smaller than 9.

This is a classy optical illusion puzzle. What more you can find except bricks in the image below?

A high school has a strange principal. On the first day, he has his students perform an odd opening day ceremony:

There are one thousand lockers and one thousand students in the school. The principal asks the first student to go to every locker and open it. Then he has the second student go to every second locker and close it. The third goes to every third locker and, if it is closed, he opens it, and if it is open, he closes it. The fourth student does this to every fourth locker, and so on. After the process is completed with the thousandth student, how many lockers are open?

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?