The most basic answer is, cars allow people to get from one place to another much quicker than many other modes of transportation and/or quicker than in times past.
no there are no humans in the movie cars
No, cars are manufactured in factories and designed by humans.
People, humans.
yes
no
No
Humans cannot physically turn their bodies into cars, but do utilize parts of their bodies during the construction phase of an automobile.
they can move humans around quicker than walking
For the same reason why humans have hearts
Cars contribute to the welfare of humanity by transportation and its less time consuming.
-Illegal drinking (alcohol,) cars, airplanes, luxaries, radio, the "American hero" - this is because ww1 benefited the U.S. positively
Humans pollute land by either not recycling or just by the cars, factories etc.