The bones of the appendicular skeleton are involved in:

Correct Answer: B

Rationale: The appendicular skeleton, including limbs and girdles, is designed for movement and locomotion. Bones like the femur and humerus enable walking and arm motion, supported by the pelvic and pectoral girdles. Protection of organs is an axial skeleton role, making 'Facilitating movement and locomotion' the correct answer.

Correct Answer: A

Rationale: Creatine phosphate stores high-energy phosphate bonds in muscle cells. During contraction, it transfers its phosphate to ADP, regenerating ATP to power myosin heads. Glycogen is a glucose store, myoglobin holds oxygen, and lactic acid is a byproduct, making 'Creatine phosphate' the correct answer.

Correct Answer: D

Rationale: The ribs, part of the axial skeleton’s thoracic cage, primarily protect thoracic organs like the heart and lungs by forming a bony enclosure. They don’t support lower limbs, protect the spinal cord (vertebral column’s role), or aid digestion, making 'Protecting the thoracic organs' correct.

Correct Answer: D

Rationale: The structure of a bone includes several layers: the periosteum (outer membrane), compact bone (dense outer layer), cancellous bone (spongy inner layer), and bone marrow (innermost part). Bone marrow, found in the medullary cavity of long bones and within cancellous bone, produces blood cells and stores fat, making it the innermost part and 'bone marrow' the correct answer.

Correct Answer: B

Rationale: Tendons are tough, fibrous connective tissues that attach skeletal muscles to bones, transmitting force to enable movement (e.g., Achilles tendon). Ligaments connect bones to bones, cartilage cushions joints, and joints are bone meeting points, not attachments, making 'tendons' the correct answer.