Answer:
The correct answer would be (B) affect organisms.
The region marked with X is the region which comes under both long term and short term changes.
Both types of changes affect organisms.
Short term environmental changes such as drought, flooding, volcanic eruption et cetera do not give enough time to the population for adaptation. The population usually either migrate or extinct.
Long term environmental changes such as global warming are gradual changes due to which organisms get enough time to adapt to the changing environment.