An abnormal increase in the lumbar curvature of the vertebral column is called

Correct Answer: C

Rationale: Lordosis is an abnormal increase in the lumbar curvature, an exaggerated inward arch (swayback), often from posture, obesity, or pregnancy, altering spinal mechanics. Scoliosis is lateral curvature. Kyphosis affects the thoracic spine outward. Extension is a normal movement, not a condition. Lordosis's focus on lumbar hypercurvature, visible in sagittal views, makes 'c' the correct answer in orthopedic terminology.

Correct Answer: B

Rationale: Epithelial tissue is avascular, lacking blood vessels, and relies on diffusion from underlying connective tissue for nutrients, as seen in the epidermis or gut lining. Vascular or highly vascularized applies to connective tissues like dermis, not epithelium. Nerve endings may penetrate epithelium, but innervation isn't a defining trait avascularity is. This lack of vasculature, ensuring a protective or selective barrier, makes 'b' the correct characteristic.

Correct Answer: B

Rationale: Melanin, produced by melanocytes in the stratum basale, determines skin color, ranging from light to dark, and protects against UV by absorbing it. Hemoglobin colors blood, visible through skin but not primary. Carotene adds yellowish tones, minorly. Keratin is a structural protein, not a pigment. Melanin's dominant role in pigmentation and photoprotection, per dermatology, makes 'b' correct.

Correct Answer: C

Rationale: Osteoclasts resorb bone, breaking down matrix via enzymes/acids to release calcium, balancing remodeling. Osteoblasts form bone, osteocytes maintain it, and chondrocytes produce cartilage, not bone resorbers. Osteoclasts' destructive role, per bone physiology, makes 'c' correct.

Correct Answer: D

Rationale: The vertebral column protects the spinal cord (not heart, a), supports the head , and allows movement/flexibility via joints e.g., cervical flexion. Heart protection is rib cage/sternum. All functions apply, per spinal anatomy, making 'd' correct.