The answer to the 3rd question is that chromosomes are tightly coiled bundles of DNA and carry many genes. For the 4th question, asexual reproduction can occur by binary fission and creates exact genetic copies of a parent. 
        
                    
             
        
        
        
Answer: In medicine, it refers to parts of the body further away from the center. For example, the hand is distal to the shoulder.
 
        
             
        
        
        
A sound wave is A wave of compression and rarefraction . 
        
                    
             
        
        
        
The most important thing is to try and extinguish a fire if a fire extinguisher is near. If not, they second most important thing is to rush out of the lab using the fire escape route and call the local fire department which will then handle the situation.