How do muscles attached to the bones move the body?

Correct Answer: B

Rationale: Muscles move bones by pulling via tendons when they contract; they can’t push (bones provide push via leverage). Automatic isn’t a mechanism, making 'pull movement only' correct.

Correct Answer: A

Rationale: The mandibular fossa, where the mandible articulates, is in the squamous portion of the temporal bone. The petrous portion houses ear structures, the tympanic portion surrounds the ear canal, and ‘articular portion’ isn’t a standard term here.

Correct Answer: A

Rationale: Bone remodeling involves osteoclasts (resorb bone) and osteoblasts (form bone), maintaining structure and calcium balance. Osteocytes maintain bone, chondrocytes form cartilage, and chondroblasts aren’t primary in bone remodeling.

Correct Answer: B

Rationale: Holding out a hand palm-up involves extending the forearm (straightening) and supinating (rotating palm upward). Flexion bends the arm, pronation turns the palm down, abduction moves away from midline, and rejection/depression aren’t standard terms here.

Correct Answer: C

Rationale: In a fetus, erythropoiesis (erythrocyte formation) primarily occurs in the liver and spleen during early development, before red bone marrow takes over after birth. Sarcoplasm is muscle cell cytoplasm, and blood is where erythrocytes reside, not where they form, making the liver and spleen the correct fetal sites.