What Was Once an Open Pasture on a Long- Abandoned

Multiple Choice

What was once an open pasture on a long- abandoned farm has changed over time,without the direct influence of humans.After the cattle had been removed,shrubs and bushes could be seen dotting the grass- covered hillsides.A few years later,small pine trees and then larger deciduous trees appeared.Now,there are so many trees and shaded regions that it is difficult to tell that this was once a field.The ecological changes in this abandoned pasture represent __________.

A) primary succession
B) secondary succession
C) disturbances
D) resilience events