The given graphs shows the productivity of an aquatic ecosystem measured in terms of dissolved oxygen produced and consumed by green plants and photosynthetic algae where PS=photosynthesis and R=respiration.

The given graph shows the amount of pollutants in four rivers P, Q, R and S. The river that can continue to support the most number of aquatic plants and animals is _______.

Answer the following Read the paragraph and answer the questions given below it. A biotic carbon atoms are circulated into the biotic form through processes like photosynthesis and respiration. Green plants convert carbon dioxide into carbohydrates and also produce carbon compounds like proteins and fats. Biotic compounds are transported from plants to apex consumers through intermediate trophic levels. After the death of all types of consumers, carbon is recycled by biotic decomposition. The carbon recycled in this way goes into the atmosphere and can be taken up by living organisms thus ensuring circulation and recycling of carbon in the biosphere. By which process do green plants convert atmospheric carbon into carbohydrates?

Answer the following Read the paragraph and answer the questions given below it. A biotic carbon atoms are circulated into the biotic form through processes like photosynthesis and respiration. Green plants convert carbon dioxide into carbohydrates and also produce carbon compounds like proteins and fats. Biotic compounds are transported from plants to apex consumers through intermediate trophic levels. After the death of all types of consumers, carbon is recycled by biotic decomposition. The carbon recycled in this way goes into the atmosphere and can be taken up by living organisms thus ensuring circulation and recycling of carbon in the biosphere. Draw a simple food chain to show transfer of carbon from plants to decomposers.

Answer the following Read the paragraph and answer the questions given below it. A biotic carbon atoms are circulated into the biotic form through processes like photosynthesis and respiration. Green plants convert carbon dioxide into carbohydrates and also produce carbon compounds like proteins and fats. Biotic compounds are transported from plants to apex consumers through intermediate trophic levels. After the death of all types of consumers, carbon is recycled by biotic decomposition. The carbon recycled in this way goes into the atmosphere and can be taken up by living organisms thus ensuring circulation and recycling of carbon in the biosphere. What process plays a significant role to ensure that carbon is available to living organisms even after the death of apex consumers?