What is required to initiate the coupling of myosin to actin?

Explanation:

The actin and myosin are the myofilaments which are involved in the contraction and relaxation of the muscle. The actin is thin filaments and contains the attachment site for the myosin but the site is blocked by the tropomyosin and troponin proteins.  

When calcium ions present in the muscle binds to the troponin molecules, it changes the conformation of the tropomyosin. This change exposes the attachment site of the myosin and then the myosin binds the troponin and causes Powerstroke and leads to contraction of a muscle.

Thus, Calcium ions is correct.

events in order:

1.       vishnu schist

2. zoroaster granite

3. bass limestone

4. hakatar   shale

5. igneous intrusion

6. shinumo quartzite

7. dox sandstone

8. tapeats limestone

9. bright angel shale

10. muav limestone

11. temple butte limestone

12. redwall limestone  

nonconformity

answer: the unkar group shows angular unconformity because the layers are turned at angle.

unconformity

answer: specifically the angular unconformity occurs between the cambrian and precambrian rocks. the dox sandstone, shinumo quartzite, hakatar shale, and bass limestone have been filled. an angular unconformity occurs between the cambrian and precambrian rocks. the dox sandstone, shinumo quartzite, hakatar shale, and bass limestone have been filled.

disconformity

answer: the disconformities aremarked irregular lines between the sedimentaryrocks layers.