You're good. K,

You are my protective God. Your job is to keep me alive. I don't have a real job, but I have a wife who does. I have lots of enemies ready to kill me. I might be weak, but all the power is in me. My country suffers from racial discrimination. Black people hate white, and white people hate black. In the meantime, visitors are having fun. Who am I?

I want to say George Bush really bad...

But I know that's not it.

Clue: It's an inanimate object. I think that's vague enough ^_^

Iran? Iraq? Afghanistan?

Or...a king on a chessboard?

Yup...It's a king. Good job!

I'm standing at a waterfall. I got 2 containers. One holds 3 litres and the other one is 5 litres. using the 2 containers, I need to get 4 litres of water. How?

And it doesn't have measuring marks or nothing.

Measuring Marks! Ha I'm smart, wait, never mind.

Well thats a tough one, but I learned how to do this when I played Star Wars Knights of the Old Republic 1.
First off you need to fill the 5L container.
Secondly you need to fill the 3L container from the 5L container. This leaves you with 3L in the 3L container, and 2L in the 5L container.
Thirdly, you empty the 3L container.
Fourthly, you fill the 3L container with the 2L from the 5L container. Now we have a 3L container with 2L in it, and an empty 5L container.
Fithly, we refill the 5L container.
Lastly, we empty 1L from the 5L container into the 3L container. This gives us 3L in the 3L container and 4L in the 5L container. Ofcourse to get the actual 4L we would have to empty the 3L container.
And thats how to do it.

Yup..That's right

My head and tail both equal are
My middle slender as a bee,
Whather I stand on my head is quite the same to you or me.
But if my head should be cut off,
the matter's true, though passing strange
Directly I to nothing change.
What am I?

we empty 1L from the 5L container into the 3L container.

AHA! I bet it will not be precise. Perhaps .999999999 liters instead of 1!

Clue: It's not a symbol, but it represents as idea. Yoy can write/draw it. You guys probably see it every day.

Lower case t?

A ? perhaps? (Probably not. Meh.)

its probably 'B'

It's not an alphabet.

No, I meant the question mark.

Is it: ?

A number

REad the riddle again and think it over.

A light bulb?

It's less than 100

Figure eight.

And it is a symbol... o_O