The right option is; B) the total variety of organisms on Earth
The total variety of organisms on Earth explains biodiversity
Biodiversity is the variety and variability of all species (different plants, animals and microorganisms) from all sources (marine, terrestrial and other aquatic ecosystem) on earth or within a particular region. Biodiversity involves genetic diversity, species diversity and ecosystem diversity which all functions together to form the complexity of life on earth.
Answer
Photosynthesis
Explanation
The sun keeps the carbon cycle working by providing light energy. This light energy is used to carry out a process called photosynthesis by organisms that are known as producers. This process creates organic matter from carbon dioxide and water. Photosynthesis thus helps maintain the activity of carbon sinks.