Final answer:
Low-back pain can have various causes and it is important to consult a health professional for an exercise program. Age does not necessarily determine the rate of back pain.
Step-by-step explanation:
The most accurate statement about low-back pain is that for many people, its underlying cause is unknown. This means that the exact reason why someone is experiencing low-back pain can often be difficult to determine.
It is important to consult an appropriate health professional, such as a physical therapist, to develop an exercise program that can help manage and reduce low-back pain. Additionally, it is not necessarily true that those between the ages of 64 to 75 years old report the highest rate of back pain in the U.S., as low-back pain can affect individuals of all ages.