In a classic experiment carried out by the biologist hopkins in the 20th century, 20 young rats were divided into two groups. one group was fed on a diet of pure carbohydrate, lipid and protein; the other was fed the same diet, but with some added milk. the rats were weighed every day. after 18 days the diets of the groups were swapped over.
why did hopkins use 2 sets of rats?
suggest some important control variables that hopkins kept constant during his investigation.

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.