John named his first son Alpha, second Beta, third Charlie and fourth Delta. What is the fifth son's name?

I am under you when I am whole.
I shift above you if you remove the first letter.
I come all around you if you remove the second as well.

Can you tell me who I am?

Can you solve this amazing hard number series problem?
7, 8, 10, 12, 16, 18 ?

A man hijacks an aeroplane transporting both passengers(8 of them) and valuable cargo. After taking the cargo, the man demands nine parachutes, puts one of them on, and jumps, leaving the other eight behind. Why did he want eight?

What does it mean?

If Bihan is 10, Anirudha is 20, and Kim and Seal are both 5, but Rikold is 10, how much is Kenniger by the same trend?

If it took eight men ten hours to build a wall, how long would it take four men to build it?

What is so fragile that saying its name breaks it?

Spot 5 differences in two Christmas tree below:

Solve the puzzle by telling what does below picture means.