Check your owner's manual. It will specify exactly which octane fuel (87, 89, 91 or other) that you should use in your car. Or maybe your car runs on Diesel, but you'd better know that already.
Help who? It helps the gas station owner who gets more profit for the more expensive fuel but it doesn't help your car at all. Your engine is designed for a specific kind of fuel (see 1.1) and running on a higher octane won't only help it run better but may cause more pollution as it doesn't burn off as efficiently.
It's a diesel fuel created from natural materials - typically vegetable or cooking oil.
Yes. Next question.
Almost none. The triggers for the front airbags are located in the bumpers so the only way you'd trigger them by drumming is if you're so busy drumming that you run into something with your car.
With the car stopped assume your regular driving position. Look at your driver's side view mirror. If you can see any of your own car your mirror is set too tight. Adjust it to the left until you can't see your own car from your normal driving position. If you lean your head to the left a bit you should then just get a glimpse of your own car.
Next, from your normal driving position, look at your rear view mirror. Can you see any of yourself? If so, adjust your mirror to the right until just after you can't see yourself anymore.
Finally, from your normal driving position, look at your passenger side view mirror. Same direction as the driver's side mirror, except you're going to adjust it to the right until you can't see your car in the mirror from the normal driving position unless you lean your head to the right.
Well, you could try a Rorschach test but diagnosis is so difficult in these modern cars. Seriously, though, pull up alongside a parked car. Then drive very slowly forward watching the car out your side window. As soon as you can't see the car out your side window stop. Now check your mirror on that side and you should see the car there. Repeat on the opposite side.
TIP: Try this in a parking lot with low traffic; rather than the street where you might have to deal with oncoming cars.
Unfortunately not. It's important that you know the history of your child's car seat especially whether or not it's ever been in a crash. Plus if you aren't the original owner how are you going to register the seat with the manufacturer? Registration is important so the manufacturer can notify you if the car seat gets recalled for any reason. Spend the money and buy a new seat, it's important.
Yes, of course. Your engine has to work a little harder to power the air conditioning condenser and that uses some fuel. Is it burning more fuel than just rolling down the windows? Depends. If your car is at a stop at the time, yes. If you're moving at highway speeds probably not - the aerodynamics of having the windows down may hurt your fuel economy more than the A/C does.
No. If you do it right it's no different than starting your own car one more time.