What conditions must be present for air to sit over a location long enough to acquire the characteristics of the land or water beneath it? i need asap

Which statement is true regarding weathering in dry environments? a) chemical weathering is absent because of a lack of humidity. b) physical weathering is usually more evident than chemical weathering. c) it is impossible to identify the type of weathering that has occurred. d) physical weathering does not play a significant role in dry environments.