Coral reefs share a symbiotic relationship with a type of algae called zooxanthellae. the hard exoskeleton that makes up a coral reef provides a safe habitat for zooxanthellae. in return, zooxanthellae use sunlight to make food for themselves and for the coral.
one of many threats to coral reefs is sedimentation run-off. sedimentation run-off clouds the water, as well as changes its chemistry.
if sedimentation run-off continues along coral reef coastlines, how would this most likely lead to the extinction of coral reefs?
a. by blocking sunlight from reaching zooxanthellae, sedimentation run-off may deprive coral reefs of the nutrients they need.
b. by causing zooxanthellae to rapidly increase in population, sedimentation run-off may greatly reduce the habitat available to coral reefs.
c. by causing coral reef waters to become overly warm, sedimentation run-off may cause coral reefs to become overheated.
d. by clouding the visibility of coral reefs from humans, sedimentation run-off may result in boats and ships destroying coral reefs.

blue

light-years

magnitude

genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).

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.