The correct option is
D All of the above.
Forests and biodiversity is key to all life forms. The richer the diversity of life, the greater the opportunity for medical discoveries, economic development and adaptive responses to such new challenges as climate change.
Forests are renewable resources which provide
(a) Habitat, food, protection to wildlife.
(b) Help in balancing CO2 and O2 of atmosphere.
(c) Improves water holding capacity of soil.
(d) Regulates water cycle.
(e) For human being, they are the source for all essential commodities like, fuel wood, timber pulp and paper etc.
(f) It provides useful products like fruits, resins, gums, essential oils, bidi wrapper etc.
Therefore, the correct answer is option D.