The mechanic opened the hood of the car to test the battery. Chris and Eli were standing right there.
Eli: Can I watch?
Mechanic: Do you have eyes?
Eli: Yes.
Mechanic: then you can watch.
It was determined that the battery needed to be replaced.
Eli: why does your car need a battery?
Chris: to help it run.
Eli: your car can't run, it doesn't have any legs.