Which of the following soil types have only weakly developed horizons?

The soil type characterized by only weakly developed horizons is Inceptisols. These soils typically form in areas with young landforms where soil development has just begun. The term "incept-" means beginning, which reflects the initial stages of soil formation. Inceptisols are usually found in environments that are less conducive to the development of distinct horizons, often due to factors like high erosion rates, relatively young geological formations, or specific climatic conditions that do not promote extensive weathering.

In contrast, Spodosols are more developed and feature prominent horizon differentiation, commonly found in regions with coniferous forests where leaching processes create a well-defined profile with distinct layers. Entisols, while they may have weakly developed horizons, are often associated with very young surfaces that have negligible soil horizons, making them less representative of this choice. Andisols, formed from volcanic ash, typically have deeper and more developed horizons due to the unique properties of volcanic materials and their capability to retain moisture and nutrients effectively.

Overall, Inceptisols stand out among these options for their characteristic stages of soil development, marked by their weakly developed horizons, making them the correct choice.