Because it allows them to breathe and function.
        
             
        
        
        
The answer to the question stated above is letter b. <span> <span>a meteor or asteroid colliding with Earth
</span></span> <span>The mass extinction at the end of the Mesozoic Era was caused by </span>a meteor or asteroid colliding with Earth. This was said to happen about 65 million years ago.
        
                    
             
        
        
        
It helps you follow procedures accurately in order to get higher, more accurate results and become a better medical professional
        
             
        
        
        
Viruses are not made out of cells, they can't keep themselves in a stable state, they don't grow, and they can't make their own energy. Even though they definitely replicate and adapt to their environment, viruses are more like androids than real living organisms.