Final answer:
Falls are the leading cause of injury and preventable mortality in older adults, mainly due to complications from osteoporotic fractures like hip fractures that may result in severe health consequences.
Step-by-step explanation:
The leading cause of injury and preventable source of mortality and morbidity in older adults is D. Falls. Osteoporotic fractures, particularly from a fall, can cause significant morbidity and can lead to further disability and early mortality. These fractures often require surgery, such as hip fracture repair, and can result in complications like deep vein thrombosis, pulmonary embolism, and pneumonia. Additionally, the elderly are more susceptible to falls due to factors like poor eyesight and balance problems, and preventative measures like removing obstacles can reduce the likelihood of falls and subsequent injuries.