What Am I Riddles

Question: I am often known as a symbol/mark, and can be used in a trend. I am created when two paths meet, but separate at the end. What am I?

Question: If you look at my face there won't be 13 any place.

Question: Some use me, while others do not.
Some remember, while others have forgot.
For profit and gain I'm used expertly, I can't be picked off the ground or tossed in the sea.
Only gained through patience and time, can you unravel my rhyme?

Question: I grow from trees and your home,
once I am grown I fall to my doom.

What am I?

Question: When you close it, you see mysterious and funny looking images. But if you open it, the mysterious images are gone. What Am I?