<span>Porosity or void fraction is a measure of the void (i.e. "empty") spaces in a material, and is a fraction of the volume of voids over the total volume, between 0 and 1, or as a percentage between 0 and 100%.</span>
        
                    
             
        
        
        
Answer:
A. the changes in the characteristics within a population that lead to survival.
Explanation:
those that cannot camoflauge or find a way to survive and reproduce, will die off.
 
        
             
        
        
        
The Sun cause That's What Gives it Food
        
                    
             
        
        
        
Stars are formed in clouds of dust and gas (nebulae.) Nuclear reactions at the center (core) of stars gives enough energy to make them shine brightly for many, many years. The exact l<span>ifetime of a star depends on its size.</span>
        
                    
             
        
        
        
Answer is A. 
Archaea requires neither sunlight for photosynthesis as do plants, nor oxygen. Archaea absorbs CO2, N2, or H2S and gives off methane gas as a waste product the same way humans breathe in oxygen and breathe out carbon dioxide. An example is chemosynthetic bacteria by sea drifts. They use chemical energy to produce vital processes to live.