altitude above sea level types of local plant cover circulation patterns of regional air masses distance to the nearest mountain range
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Going north from the equator, hot, moist climates are replaced by hot, dry climates. The boundary between these two climate types is determined by which factor?
Possibilities:
- altitude above sea level
- types of local plant cover
- circulation patterns of regional air masses
- distance to the nearest mountain range

circulation patterns of regional air masses