Do You See It?

What is the relationship between these matchstick pictures below?

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

I am never scared but became petrified and can’t live in a house but would die to make one. What am I?

A doctor and a boy were fishing. The boy was the doctor’s son, but the doctor was not the boy’s father. Who was the doctor?

I am a prime number.
The double of myself is equal to the square of me.

which number am I?

How can I get the answer 24 by only using the numbers 8,8,3,3?

You can use the main signs add, subtract multiply and divide.

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?

Name the three-letter word that can complete the below words?

A) L O _ _ _ E
B) E D U _ _ _ E
C) _ _ _ E R
D) _ _ _ T L E

I have no life, but I can die. What am I?