| (a) |
| Actin | Myosin |
| 1. The light band in the myofibril contain actin protein | The dark band in the myofibril contain myosin protein |
| 2. Actin filaments are thin | Myosin filaments are thick. |
| (b) |
| Red Muscles | White Muscles |
| 1. Muscles which contain high amount of oxygen storing red colour pigment called myoglobin appear red. | White muscles do not contain myoglobin. So they are white in colour. |
| 2. They contain plenty of Mitochondria. | The number of mitochondria is few. |
| 3. These are aerobic muscles. | They depend on anaerobic process for energy. |
| (c) |
| Pectoral Girdle | Pelvic Girdle |
| 1. The pectoral girdle helps in the articulation of the upper limbs. | The pelvic girdle helps in the articulation of the lower limbs. |
| 2. The pectoral girdle consists of a clavicle and a scapula. | The pelvic girdle consists of two coxal bones. |