Asap -What factors make it difficult for scientists to classify world climate regions? A
B
C
D

I would say C

Explanation:

changing conditions and a lack of something are always negative factors

within these regions are all the major types of biomes in the world. a biome is a community of animals and plants spreading over an extensive area with a relatively uniform climate. some diverse biomes represented in north america include desert, grassland, tundra, and coral reefs.