Out of four images which one is the odd one out?

There is an English word that can be used up to four times in a row without modifying the spelling and form a valid grammatical sentence.

Do you know what word is that?

What has 13 hearts but no other organs?

A train leaves from point A for point B at 80 mph. After half an hour, another train leaves from point B for point A at 60 mph.

Which of the trains will be farther from point A when they meet ?

Can you complete the sequence?

192, 021, 222, 324, 252, 627, 2__, 9__?

What begins with T, ends with T, and has T in it?

All of you like to eat me. I am a five-lettered word. Remove the first two and I turn into an infamous animal. Remove just the first and I become a heinous crime. Remove the first and the last and you can groove on me.

Can you guess who am I?

How can you spell "White of an egg" in one word?
Hint: I know you can spell coke, poke, and joke.

With the help clues provided in the image, can you find the 5 digit key?

There are 20 people in an empty, square room. Each person has full sight of the entire room and everyone in it without turning his head or body, or moving in any way (other than the eyes). Where can you place an apple so that all but one person can see it?