| I: | Z line | an attachment point for actin molecules | 
| II: | M line | an attachment point for myosin molecules | 
| III: | A band | a band where only actin molecules are found | 
| IV: | I band | a band where only myosin molecules are found | 
| I: | It is a polymerised protein. | 
| II: | The HMM component is the head and short arm. | 
| III: | The globular head is an active ATPase enzyme and has binding sites for ATP and active sites for actin. | 
| I: | the ‘I’ bands get reduced | 
| II: | the ‘A’ bands retain the length | 
| I: | cervical region with 7 vertebrae | 
| II: | thoracic region with 12 vertebrae (12) | 
| III: | lumbar region with 4 vertebrae | 
| IV: | sacral (2-fused) and coccygeal (2-fused) regions | 
| 1. | is a U-shaped bone in the neck | 
| 2. | is a flat bone on the ventral midline of thorax | 
| 3. | is a small bone commonly found embedded within a muscle or tendon | 
| 4. | provides attachment to floating ribs | 
| Statement I: | Each rib is a thin flat bone connected ventrally to the vertebral column and dorsally to the sternum. | 
| Statement II: | Each rib has two articulation surfaces on its ventral end and is hence called bicephalic. | 
| COLUMN I | COLUMN II | ||
| A | Skeletal | P | Unstriated and Involuntary | 
| B | Smooth | Q | Striated and Voluntary | 
| C | Cardiac | R | Striated and Involuntary | 
| A | B | C | |
| 1. | P | Q | R | 
| 2. | R | Q | P | 
| 3. | Q | P | R | 
| 4. | P | R | Q | 
| I: | is a specialised tissue of endodermal origin. | 
| II: | contributes about 20-30 per cent of the body weight of a human adult. |