Final answer:
Back swamps form in freshwater marshes and swamps with slow water flow. They have stagnant water with low oxygen levels and a low pH, making nitrogen less available to plants.
Step-by-step explanation:
Back swamps typically form in freshwater marshes and swamps, where water flow is slow and steady. They are especially common in areas with clay bottoms and poor water percolation. Back swamps are characterized by stagnant water with low oxygen levels, which can lead to the buildup of organic and other acids. The low pH of the water makes nitrogen less available to plants, creating a challenge for plant growth.