AI-generated practice question — model-generated for extra practice, not a previous-year CBSE board question.
The brain is protected by a bony box (cranium/skull) and a fluid-filled balloon (cerebrospinal fluid); the spinal cord is protected by the vertebral column (backbone).
The passage from section 6.1.3 directly states both protective structures. Examiners expect you to name the bony box for the brain and the vertebral column for the spinal cord — two structures for the 1 mark. Mentioning the fluid-filled balloon is a bonus detail but not strictly required.