Final answer:
The statement is true; the ribs and sternum are classified as flat bones because they are thin, broad, and provide protection and muscle attachment surfaces. The correct option is A.
Step-by-step explanation:
The statement that the ribs and sternum are classified as flat bones because they are thin and broad is true. These bones embody the characteristics of flat bones, providing extensive protection for organs and offering broad surfaces for muscle attachment.
Notable examples of flat bones, in addition to the sternum and ribs, include the scapulae (shoulder blades) and cranial (skull) bones. Flat bones can also be somewhat curved, despite their categorization.