Which of the following are essential for the maintenance of balance in the ecosystem?

The correct option is D All of these

• The water cycle, carbon cycle, and nitrogen cycle are essential for maintaining balance in an ecosystem.
• The water cycle is the cyclic movement of water on earth and its atmosphere. Water evaporates from the surface of the earth, rises into the atmosphere, cools and condenses as snow or rain clouds, and falls again to the surface as precipitation.
• The carbon cycle is the movement of carbon from the atmosphere to the Earth and then back into the atmosphere. Photosynthesis utilizes carbon dioxide and releases oxygen while respiration utilizes oxygen and gives back carbon dioxide.
  
• The nitrogen cycle is the process by which atmospheric nitrogen is fixed by certain bacteria and converted into usable nitrogenous compounds which are used by plants. Nitrogen is released back into the atmosphere by the process of denitrification.
• So, the correct answer is option D