Answer: C.  Dead snake fossilizing underground. 
A fossil fuel is the fuel that is formed by natural processes, such as anaerobic decomposition of dead plants and animals underground. These organisms and their remains remain deep inside the depth of numerous layers of soil resulting in fuel produced after millions of years. A carbon sink refers to a natural or artificial reservoir that stores and absorbs atmospheric carbon by physical and biological process. The formation of fossil fuel inside the earth is carbon sink.  
Dead snake will be added as a matter on which biological activity called as decomposition will take place. The organic matter of dead snake will be decomposed by microbes in the soil. The organic matter being the source of carbon, after decomposition will become the reservoir of carbon in the form of fossil fuel. 
Therefore, dead snake fossilizing underground is the example of carbon source becoming a carbon sink. 
 
        
             
        
        
        
Highly porous and permeable
Explanation:
Compared to other types of rock layers, an aquifer is highly porous and permeable. 
Aquifers are always the target when prospecting for ground water in a formation. 
- Porosity is the amount of void spaces in a rock. 
- Aquifers are highly porous . 
- Permeability is the inter-connectivity of the void spaces and their ability to transmit fluids. 
- Aquifers have very high permeability compared to other rock types. 
In terms of permeability and porosity, an aquifer is higher porous and permeable. 
learn more: 
Biogeochemical cycle brainly.com/question/3509510
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Different versions of a gene are called alleles. Alleles are described as either dominant or recessive depending on their associated traits.
 
        
             
        
        
        
A seismometer is used to measure the motion in the ground caused by earthquakes, volcanoes, or explosives.