Final answer:
Arthritis, which includes over 100 forms like osteoarthritis, is a true condition causing pain and stiffness in joints, mainly due to inflammation and cartilage wear.
Step-by-step explanation:
The statement that arthritis refers to a disease causing pain or stiffness in skeletal joints is True. Arthritis is a common disorder involving inflammation of the synovial joints, which often results in significant pain, swelling, stiffness, and reduced mobility. Among the more than 100 forms of arthritis, the most prevalent type is osteoarthritis (OA), often associated with aging and the degenerative 'wear and tear' of articular cartilage. Risk factors include joint injury, physically demanding jobs, certain sports, and being overweight. OA develops as the cartilage wears down, leading to increased bone pressure, pain, and inflammation. Treatments for osteoarthritis focus on alleviating pain through lifestyle changes such as weight loss and low-impact exercise, medications, and in severe cases, joint replacement surgery may be considered.