Answer:
A single organism can adapt to a cold environment by growing long hair. 
Explanation:
 
        
                    
             
        
        
        
Answer:
Cardiovascular is the correct option
 
        
                    
             
        
        
        
Answer:
Natural selection can be described as a phenomenon in which individuals of a population which are better adapted to survive in an environment are favored by nature as compared to the individuals of the population which lack better characteristics to survive in the environment.
Through natural selection, evolution occurs and the allelic frequency changes over a period of time. The process of evolution as well as change in the allelic frequencies does not occur just by a single individual, rather it is a collective effort which takes a lot of time. Hence, we say that natural selection changes the population and not a single individual. 
 
        
             
        
        
        
Answer:
The molecules in a solid are more closely packed than those in a gas. Gas molecules are VERY spread apart, which is why we cannot see them.
Explanation: