What is the longest word in the dictionary?

Be active and find the killer in the picture Riddle below.

How many minutes are there in Feb 2017?

Note: The shortest answer is the correct answer.

I go up and I go down.
I go up towards the beautiful sky and down toward the green ground.
I am present tense.
I am past tense too
Children love me.

Who Am I?

How many times can you subtract the number two from the number fifty?

There are two guys standing face to face in a room. On a wall, there is a clock. One of those is a prophet. He tells the other guy that he will be stabbed in the back in five minutes.

Shocked to hear that, the other guy stares at the clock. Just after the five minutes, he is stabbed on the back. Can you tell what happened?

I have one of the three numbers: 1, 2, or 3 in my mind. I speak only truth. You can ask me just one question for which I will only reply in yes or no or don't know. What question will you ask from me so that you are able to know the number?

Can you spot the hidden girl in the picture below?

It walks on 4 when its young, walks on 2 when it's older, and walks on 3 when its very old?

Railroad Crossing, look out for the cars. Can you spell that, without any R's ?