Well to understand productivity you must understand how humans started working for the benefit of themselves and community.
A long time ago there ware 4 simple roles a farmer, hunter or gatherer and solider all of which ware needed for basic survival. Then there was a revolution and these basic jobs became more and more unpopular and new jobs ware appearing through new discoveries. Now to make a simple meal we don't need to be a farmer and know hunter and gatherer we just go to store buy it and cook it. What is productivity? Productivity is a number of products made by a single person or bigger communities like country in certain amount of time. What that basically means is that we spend less time to produce. You might say this degrades the quality of products but it certainly increases each individual efficiency.
        
             
        
        
        
Answer:
A. 
Explanation:
The key word is simultaneously when it comes to parallel computing. Although the option <em>could </em>potentially be C, it's more likely to be A because it's "more right" in the words of my old English teacher. This is because A implies them working on it at the same time to reach the goal more effectively (another key word). 
 
        
                    
             
        
        
        
Answer: 1. They shake the ground
                2.  They travel through solids
                 3. They vibrate from side to side
Explanation: Hope this helps!
 
        
             
        
        
        
Answer:
do your work 
Explanation:
yourself don't say to anyone