The correct option is A bio-diversity
Forest biological diversity refers to all life forms found within forested areas, and their ecological relevance. Forests serves as habitats for two-thirds of terrestrial animal and plant species, prevent soil erosion, water run-off, maintain the chemical balance of soil, air and water, recycle nutrients, break down pollutants, clean air and water, are vital to watershed protection and soil formation, and play a major role in regulating climate. All these factors allows plants and animals to live and breed naturally without interference in the forests.