Final answer:
A guaranteed insurability rider can be added to a juvenile's life insurance policy to allow additional insurance purchases without further health exams.
Step-by-step explanation:
In life insurance policies, a rider that can be added to a juvenile's policy to allow the purchase of additional amounts of life insurance in the future without requiring a medical examination is known as a guaranteed insurability rider. This type of rider is especially valuable as it ensures that the insured individual will be able to increase their coverage regardless of any changes in health that might otherwise make them uninsurable or increase their premiums significantly. The guaranteed insurability rider can be invoked at specific times or life events stipulated by the policy, allowing the policyholder to adapt their coverage as their life changes.