Which type of rock does not belong in the same category as the others?
a. slate
b. skarn
c. marble
d. quartzite

Slate, Skarn, Marble, and Quartzite are Metamorphic Rocks. 
BUT SKARN is the type of rock that does not belong in the same category as the others.

Slate metamorphosed from mudstone. Marble metamorphosed from limestone. Quartzite metamorphosed from sandstone. All these rocks retain their solid forms.

Skarn is a metasomatic rock composed of calc-silicate minerals. Skarn is formed at the contact zone between carbonate rocks and silicic magma. Skarn is often rich in hydrothermal ore minerals. Skarn as a metamorphic rock is dissolved under metasomatic process and hardens back into a rock.

The return of the wolf to yellowstone national park will probably affect the bird population to some degree, not significantly. while wolves will hunt birds when necessary, they prefer to hunt larger prey. the bird population will most likely only be affected when hunting is scarce for the wolves. birds of prey will also probably not be affected as much as other birds who spend more time on the ground hunting for food as the tend to spend more time in the air or in trees since they do not need to stay on the ground for long due to the nature of the way they hunt.

only b