Final answer:
The incomplete question about what children ages six to 18 are required to ride lacks context, but likely refers to safety regulations for transportation. This can relate to car seats for young children or helmets for bicycles, depending on the mode of transportation discussed.
Step-by-step explanation:
The question regarding children ages six up to 18 and what might be required for them to ride is incomplete as it does not specify what they are required to ride. However, contexts such as safety regulations involving transportation often dictate that children within certain age groups ride with specific safety restraints or devices, like car seats or booster seats for younger children, or that they should be accompanied by an adult when using public transportation. For example, children ages 6-13 might be required to ride in a booster seat if they are not tall enough to properly use a standard seatbelt in a vehicle. Similarly, there might be requirements for children to wear helmets while riding bicycles. Without full context, the specific requirement remains unclear.