1641. Which of these is not a region of the spinal cord ?
A. Thoracic
B. Pelvic *
C. Lumbar
D. None of these
1642. The shape of the external ear is due to :
A. Elastic cartilage *
B. Fibrocartilage
C. Articular cartilage
D. None of these
1643. The external surface of the stomach is covered by :
A. Mucosa
B. Serosa *
C. Parietal peritoneum
D. None of these
1644. Which of the following is not a human organ system ?
A. Integumentary
B. Muscular
C. Epithelial *
D. None of these
1645. Which of the following does not depend on the depth of the aquatic environment in a predictable way?
A. Salinity *
B. Temperature
C. Penetration by sunlight
D. None of these
1646. The quantity of available nutrients __________ from the lower levels of the energy pyramids to the higher ones :
A. Increases
B. Decreases *
C. Remains stable
D. None of these
1647. Which of the following is not a major sub division of the biosphere ?
A. Hydrosphere
B. Stratosphere *
C. Lithosphere
D. None of these
1648. Vaccination is synonymous with __________ immunity :
A. Natural active
B. Artificial passive
C. Artificial active *
D. None of these
1649. When a partient’s immune system becomes reactive to a drug , this is an example of :
A. Super infection
B. Drug resistance
C. Allergy *
D. None of these
1650. What is the smallest unit of heredity ?
A. Chromosomes
B. Gene *
C. Nucleotides
D. None of these