The skull houses the brain, which sits in the cranial ... .

Correct Answer: A

Rationale: The brain resides in the cranial cavity, a well-defined space within the skull formed by the cranial bones. 'Hole' and 'pit' are vague and not standard terms for this structure.

Correct Answer: B

Rationale: Ribs 11 and 12 are 'floating ribs,' lacking any attachment to the sternum, unlike false ribs (8–10), which connect indirectly via cartilage. 'Loose' is not a standard term here.

Correct Answer: A

Rationale: The ulna is slightly longer than the radius and features the olecranon (elbow projection) and coronoid process (anterior projection), forming the elbow joint with the humerus. The radius lacks these.

Correct Answer: A

Rationale: The tibia, the larger leg bone, bears most of the body’s weight and has a fibular notch distally to articulate with the fibula, stabilizing the ankle.

Correct Answer: D

Rationale: The sternum (breastbone) is part of the axial skeleton, forming the thoracic cage with the ribs to protect the heart and lungs. Scapula (shoulder blade), humerus (upper arm), and femur (thigh) are appendicular skeleton bones, involved in limb movement, not axial support.