Riddles :D

I know that we already have 2 other riddle blogs (one from Butterfly and the other from Cheyser), but still, we DID have four name guessing blogs, right? So, why not another riddle blog? :P

Riddles

1. What do you call "a car's best friend?"
2. What type of car only follows it's tracks? (Aka. Only moves along a certain route) (Answer: Cable cars / Winner: Momamoni)
3. What plane flies but carries no passengers? (Answer: Paper planes / Winner: Cheyser the cave dragon)
4. There is something in our body that we can't see but can feel, if we can't feel it we're dead, what is it? (Answer: Heartbeat / Winner: Oomagooma25)
5. What do we do when an ant bites us? (One word, it's a color) (Answer: Yellow - Yell'Ow' / Winner: Momamoni)
6. If 1+1=4, 1+1+1=9, 2+2=8, 2+2+2=18, then what is 4+4+4=? (Answer: 36 / Winner: Cduncan)
7. What comes down but never goes up? (Answer: Rain / Winner: User:Cheyser the cave dragon)
8. What can move left and right, but not forwards and backwards? (Answer: Crab / Winner: Cheyser the cave dragon)
9. With just one finger, you can go from New York to China without moving anywhere, why? (Answer: Because you're using a globe or map / Winner: Cheyser the cave dragon)
10. You can see me at the night, but not at daylight, I have light, but it's not mine, what am I? (Answer: The Moon / Winner: Cheyser the cave dragon)
11. You and I, We are twins, but I can't touch you, what am I? (Answer: Reflection / Winner: Momamoni)
12. I decide your fate, when I say go, you go, when I say stop, you stop, you disobey me, you may die, what am I? (Answer: Traffic lights / Winner: Momamoni)
13. I am the princess of the world, yet no one's the prince, but instead the murderers, what am I?
14. I am a fan, but I don't give you breeze, why? (Answer: Because you're someone's fan / Winner: Cheyser the cave dragon)
15. I am a type of plant, outside I'm dull, inside I'm beauty. What am I? (Answer: Cactus / Winner: Cheyser the cave dragon)
16. I symbolize the inside of you, the wall surrounding you, the rage of animals and the rage of drivers. What am I?
17. What type of vegetable do cars eat?
18. Take me, and I'll be born from a tiny rectangular portal;
    Take me out, and I'll be in the same world as you.
    Put me in jail and hang me, and I'll forever be your memory;
    Make me fall, and my jail will break, but not me.
    What am I?