Concept: This question tests your knowledge of the protective structures of the central nervous system, specifically the spinal cord.

Why (A) is correct: The spinal cord is a delicate structure that is part of the central nervous system. It is enclosed and protected by the vertebral column (also known as the backbone or spine), which is made up of individual bones called vertebrae.

Why other options are wrong:

• (B) Skull: The skull protects the brain, not the spinal cord.
• (C) Sternum: The sternum (breastbone) is part of the rib cage and protects organs in the chest, like the heart and lungs.
• (D) Ribs: The ribs form the rib cage and protect the thoracic organs, but not the spinal cord directly along its entire length.

NEET Tip: Remember that the central nervous system (CNS) consists of the brain and spinal cord. The brain is protected by the skull, and the spinal cord is protected by the vertebral column. Both are further protected by meninges and cerebrospinal fluid.

Correct Answer: (A)