Final answer:
Pine flatwoods are prone to flooding due to impermeable layers beneath the soil such as clay, which prevent water from draining effectively.
Step-by-step explanation:
Pine flatwoods flood easily during the rainy season because of the impermeable layers under the soil that water can't drain through. The correct answer is c) Impermeable layers. These layers often consist of materials with low percolation rates, such as clay, which makes it difficult for water to move down through the soil profile. In contrast, sand deposits typically have high porosity and would allow for better water drainage. Freshwater marshes, swamps, and other types of wetlands typically have soils that are permanently or periodically saturated with water, but the water movement is characteristically slow and steady rather than rapid.