If the number of trees on earth continues to decrease significantly, what might be the result?

A significant decrease in trees can reduce the oxygen released and allow more carbon dioxide to build up. Without tree roots to hold soil in place, erosion may increase, and animals can lose habitat, reducing biodiversity. Trees also affect nutrient cycles, including nitrogen and phosphorus, and the movement of water through ecosystems. Since both a and b describe possible effects, the best answer is “a and b.”

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