Leaving sharp objects within reach of children is a potential hazard and can lead to injuries. The other options are all recommended safety measures for preventing falls in young children.

Motor vehicle crashes are the leading cause of unintentional injury-related deaths in children under the age of 5.

Leaving young children unsupervised near water is a potential hazard and can lead to drowning. The other options are all recommended safety measures for preventing drowning in young children.

Children should start wearing a bicycle helmet as soon as they start riding a bicycle, typically around 1 year old.

Leaving matches and lighters within reach of children is a potential hazard and can lead to burns. The other options are all recommended safety measures for preventing burns in young children.

Children should start using a booster seat in a car once they reach 4 years old and weigh at least 40 pounds.

Leaving medications and household chemicals within reach of children is a potential hazard and can lead to poisoning. The other options are all recommended safety measures for preventing poisoning in young children.

Children should start wearing a helmet when riding a scooter as soon as they start riding, typically around 2 years old.

Leaving toys and other objects on stairs and walkways is a potential hazard and can lead to falls. The other options are all recommended safety measures for preventing falls in older children.

Children should start wearing a helmet when riding a skateboard as soon as they start riding, typically around 5 years old.

Swimming alone in unsupervised areas is a potential hazard and can lead to drowning. The other options are all recommended safety measures for preventing drowning in older children.

Children should start wearing a helmet when riding a bicycle as soon as they start riding, typically around 1 year old.

Leaving matches and lighters within reach of children is a potential hazard and can lead to burns. The other options are all recommended safety measures for preventing burns in older children.

Children should start using a booster seat in a car once they reach 4 years old and weigh at least 40 pounds.

Leaving medications and household chemicals within reach of children is a potential hazard and can lead to poisoning. The other options are all recommended safety measures for preventing poisoning in older children.