What is true about Entisols?

Entisols are a soil order characterized by their minimal development and diverse formation processes, often resulting from recent geological activity. One of their key features is the lack of significant horizon development, which is why they may not exhibit pronounced clay accumulation seen in more developed soils like Vertisols or Argillic horizons.

The statement that Entisols can have Aq, Psamm, or Fluv suborders is true because these suborders represent different environmental conditions and processes that influence their formation. For example, the Aq suborder indicates saturation in wetland areas, Psamm represents sandy soils typically found in arid regions, and Fluv indicates soils formed from alluvial deposits near water bodies. These suborders highlight the versatility of Entisols in various landscapes and climates.

The other statements do not accurately represent Entisols. While they can contain organic matter, they are not devoid of it entirely, as organic horizons can be present in certain conditions. It's also not accurate to say that they always develop in humid climates, as Entisols can be found in a variety of climates ranging from arid to humid. The depth of clay accumulation is a feature of more developed soils and does not apply to the generally minimal profile development of Entisols.