Final answer:
Leaving a child who is 6 years old or younger alone in a car is illegal and can result in charges of neglect or endangerment. Law's regarding child supervision vary by state, but supervision is always advisable for safety.
Step-by-step explanation:
It is illegal to leave any child who is 6 years old or younger alone in the car without supervision. Each state has different laws regarding the age at which a child can be left alone, but leaving a child who is 6 or younger unattended is universally viewed as reckless and can result in legal consequences. However, some laws and guidelines may consider factors such as the child's maturity level, the safety of the environment, and the length of time unattended. It is always safer to err on the side of caution when it comes to the supervision of young children in potentially dangerous situations. Not only is this crucial for the children's safety, but failing to do so could also result in charges of neglect or endangerment.