Answer:
A
Explanation:
An isolated system can NOT exchange energy or matter with it's surroundings. This is why it is isolated.
Temperate grasslands are composed of a rich mix of grasses and forbs and underlain by some of the world’s most fertile soils. Since the development of the steel plow most have been converted to agricultural lands.
We all know that independent is containing the x and the dependent is the y. Meaning that the y depends on the x.
The KT boundary marks a mass extinction event. the KT boundary is the time between the Cretaceous and Tertiary periods. An asteroid hit the earth at the end of the Cretaceous and that caused the end of the Cretaceous period. Before the KT boundary, pollen from angiosperms and gymnosperms is high. After the meteor hits the earth, a mass extinction occurs and the amount of pollen from gymnosperms and angiosperms decreases dramatically, while the amount of spores from ferns increases. During the Cretaceous period there were many species of gymnosperms and angiosperms but they disappeared at the KT boundary, when the asteroid hit the earth.
