In four steps you need to move the word 'cold' From 'warm' by replacing one alphabet at a time such that every word formed at each step is acceptable in English Dictionary.

John enters a small room. The Door Closes.
When the door opens, John is in a larger room.

Explain?

Before Mount Everest was discovered, what was the highest mountain in the world?

When I go in I might cause pain. I cause you to spit and ask you not to swallow. I can fill your hole. What am I?

John had a bag containing colourful marbles. The colours are red, green and blue. The total number of marbles he had in his bag was 60. There are 4 times as many red marbles as green marbles. 6 more blue marbles than green marbles. How many marbles of each colour did John have?

A new Engineering building containing 100 offices had just been completed. John was hired to paint the numbers 1 to 100 on the doors. How many times will John have to paint the number nine (9)?

Lifeless eyes on my smiling face and watch your child's sleeping place. In their dreams they hold me tight. What am I?

Samuel was out for a walk when it started to rain. He did not have an umbrella and he wasn't wearing a hat. His clothes were soaked, yet not a single hair on his head got wet. How could this happen?

Readers with the eyes of a hunter can find the snake in the field. Can you? Test your puzzle-solving skills now!

I am a type of vehicle that has two wheels and is powered by humans. What am I?
Hint 1: You can ride me for exercise.
Hint 2: I am environment-friendly.