Which of the following statements regarding eutrophication are correct ?
(i) Eutrophication is the natural ageing of a lake by nutrient enrichment of its water.
(ii) Pollutants from human activities like effluents from the industries and homes can radically accelerate the aging process of a lake. This phenomenon is called as cultural or accelerated eutrophication.
(iii) The plant nutrients responsible for eutrophication are nitrates and phosphates.
(iv) These phosphates and nitrates accelerate the growth of algae, which utilise oxygen and may deoxygenate the water to kill the fish and other aquatic animals.