What is the function of the erector spinae?

Correct Answer: C

Rationale: The erector spinae, a muscle group along the spine (e.g., iliocostalis, longissimus), provides postural support, extending the back to maintain upright stance against gravity. Arm movement involves deltoid or latissimus dorsi. Pelvic stabilization is more gluteal or abdominal. Rotation involves obliques or rotatores, not primarily erector spinae, which focuses on extension. Its role in posture, critical for standing/sitting, makes 'c' the correct function.

Correct Answer: B

Rationale: The body of a cervical vertebra (C3-C7) is oval-shaped when viewed superiorly, wider side-to-side than front-to-back, supporting the neck's weight and mobility. Round doesn't fit cervical bodies aren't circular. Heart-shaped applies more to sacral vertebrae in some contexts, not cervical. Triangular describes vertebral foramina, not bodies. The oval shape, seen in anatomical diagrams, optimizes load distribution and flexibility, making 'b' the correct description.

Correct Answer: B

Rationale: Abduction moves limbs or fingers away from the midline, like spreading arms or fanning fingers, driven by muscles like deltoid or abductor digiti minimi. Adduction brings them toward the midline. Rotation twists around an axis. Extension straightens joints. Abduction's lateral movement, per anatomical planes, makes 'b' the correct action.

Correct Answer: A

Rationale: A tissue is a group of similar cells with a common function, like muscle or epithelial tissue, forming the basic structural units between individual cells and organs in the body's hierarchy. A type of organ is incorrect organs comprise multiple tissues (e.g., skin includes epithelium and connective tissue). A fluid might describe blood, a tissue, but not all tissues are fluids (e.g., bone). A structural protein like collagen exists within tissues, not as tissue itself. The definition of tissue as cellular aggregates with shared roles, per histology, makes 'a' the correct answer.

Correct Answer: C

Rationale: The stratum basale, the deepest epidermal layer, produces new skin cells via mitosis of basal keratinocytes, regenerating the epidermis as cells move upward. Stratum corneum is dead, keratinized cells. Stratum granulosum is for keratinization, not division. Stratum spinosum strengthens, not generates. The basale's role as the proliferative base, per skin histology, makes 'c' correct.