FOUR RIDDLES

1)

Some people live in that of others,

Some are afraid of their own;

Some people hide in them,

With "eye" some disguise with them.

2)

Arms that can't hug,

Legs that can't run.

3. One hundred feet in the air, it lies with its back on the ground.

4. I'm a six-letter word. My whole is a solution to a problem, my first three a stage of sleep.

HINT:

3. Think about possible double meanings of certain words.

4. The three letters are an acronym.

Answers:

1. Shadow(s)

2. Chair

3. A dead centipede

4. REMedy (Rapid Eye Movement)