Yes, there are many US citizens who have cars, but there are many US citizens (like those who are children, those who can't afford cars, etc.) who do not have cars. There are over 250 million registered motor vehicles in the US.
Yes, provided they have a valid driver's license. Many people in the US on student visas own and drive cars.
Yes, if they are born in the US, they are US citizens.
No.
Yes, US citizens can travel to Australia.
Yes, US citizens can travel to Japan.
Yes, US citizens can travel to Singapore.
Yes, US citizens can travel to Uzbekistan.
Yes, US citizens can travel to the Philippines.
how many cars in the us today
it has set laws in it that protect citizens
There are 254.4MM registered cars in the US according to a 2007 DOT study. The US Census estimates there are ~310MM people in the US as of 7/2010. I'm not sure how many are citizens - perhaps ~300MM for a round number. That means ~0.85 registered vehicles for every man, woman and child in the US (or 85 vehicles per 100 people)
Bears, wolves, hockey teams, Ford cars, White trucks, Walmart stores, ranches, wild horses, rodeos, armed police, and zillions of other things.