Which part of the scapula articulates with humerus?

Correct Answer: B

Rationale: The glenoid cavity, a shallow depression on the scapula's lateral edge, articulates with the humerus's head, forming the shoulder joint (glenohumeral), allowing wide mobility. The acromion connects to the clavicle, not humerus. The clavicle isn't part of the scapula. The coracoid process anchors muscles, not the humerus. The glenoid's role as the humeral socket, per shoulder anatomy, makes 'b' the correct answer.

Correct Answer: B

Rationale: Transitional epithelium lines the urinary bladder, a stretchy, stratified tissue that expands as the bladder fills and contracts when empty, preventing leaks. Simple columnar suits digestive tracts (e.g., intestines), not stretchy organs. Stratified squamous protects (e.g., esophagus), not stretching. Simple cuboidal is for secretion/absorption (e.g., kidneys), not expansion. Transitional's unique adaptability to volume changes, per urinary system histology, makes 'b' correct.

Correct Answer: C

Rationale: The hypodermis, or subcutaneous layer, is mainly adipose tissue, storing fat for insulation and energy, cushioning underlying structures. Epidermis is epithelial, dermis is connective with glands/vessels, and stratum granulosum is an epidermal sublayer, none fat-dominated. Hypodermis's fat content, per skin structure, makes 'c' correct.

Correct Answer: B

Rationale: Parathyroid hormone (PTH) increases blood calcium by stimulating osteoclasts, kidney reabsorption, and vitamin D activation, countering low levels. Calcitonin lowers calcium, depositing it in bones. Estrogen and testosterone affect bone density, not directly calcium. PTH's regulatory role, per endocrinology, makes 'b' correct.

Correct Answer: A

Rationale: Sutures are immovable, fibrous joints connecting skull bones (e.g., coronal), locking them post-growth. Fontanels are infant soft spots, closing to sutures. Joint is broad, but suture is specific. Ligaments connect bones elsewhere. Sutures' cranial role, per anatomy, makes 'a' correct.