Correct Answer is A. They were able to increase their productivity due to the popularity of tractors.
 
        
             
        
        
        
Answer:
Ionic bond
Explanation:
A bond formed by the electrical attraction between two oppositely charged ions is an Ionic bond.
 
        
             
        
        
        
Answer:
<u><em>Some cartilage becomes bone through ossification during childhood development. </em></u>
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Explanation:
You forgot to include options.