| 1. | Aldosterone and Prolactin | 
| 2. | Progesterone and Aldosterone | 
| 3. | Estrogen and Parathyroid hormone | 
| 4. | Parathyroid hormone and Prolactin | 
| 1. | binds to troponin to remove the masking of active sites on actin for myosin. | 
| 2. | activates the myosin ATPase by binding to it. | 
| 3. | detaches the myosin head from the actin filament. | 
| 4. | prevents the formation of bonds between the myosin cross bridges and the actin filament. | 
The pivot joint between atlas and axis is a type of:
| 1. | Cartilaginous joint | 2. | Synovial joint | 
| 3. | Saddle joint | 4. | Fibrous joint | 
Out of ‘X’ pairs of ribs in humans only 'Y' pairs are true ribs. Select the option that correctly represents values of X and Y and provides their explanation:
| 1. | X=12, Y=5 True ribs are attached to vertebral column and sternum on the two ends. | 
| 2. | X=24, Y=7 True ribs are dorsally attached to vertebral column but are free on ventral side. | 
| 3. | X=24, Y=12 True ribs are dorsally attached to vertebral column but are free on ventral side. | 
| 4. | X=12, Y=7 True ribs are attached dorsally to vertebral column and ventrally to the sternum. | 
Name the ion responsible for unmasking of active sites for myosin for cross-bridge activity during muscle contraction.
(1) Calcium
(2) Magnesium
(3) Sodium
(4) Potassium.
| 1. | junction leading to fatigue | 
| 2. | high concentration of ca++ and Na+ | 
| 3. | decreased level of oestrogen | 
| 4. | accumulation of uric acid leading to inflammation of joints |