שאלה | Most soil degradation of the contaminants that migrate from the land surface occurs in the upper 1 m of the vadose zone

Most soil degradation of the contaminants that migrate from the land surface occurs in the upper 1 m of the vadose zone

		This sentence is incorrect.
		This sentence is correct because micro-organisms cannot move deeper into the profile
		This sentence is correct because, typically, there is more oxygen and more organic carbon in the upper 1 m of the vadose zone.
		This sentence is correct because of the preferential flow pathways that only exist in the upper 1 m of the vadose zone.