Mustufa ran the 100-meter and 200-meter races (but the one he had trained for the hardest was the 400-meter competition).
This is the only answer that is grammatically correct. Parentheses cannot just be place anywhere in a sentence. They are used to add extra information for clarity or information that is an aside). An aside is something that is not the main part of the discussion. In this sentence, the main point is that Mustufa ran the sprint races. The extra information is that he trained for the mid-distance race. 
 
        
                    
             
        
        
        
Answer:
You recognise your ability to accomplish goals. You're optimistic about the future as you set goals and achieve them. Deep down inside, you know you can do anything. You treat yourself kindly.
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Answer:
The social costs of cellphone usage can be defined as a depreciation of social interactions.
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Answer:
George Orwell changed during the Spanish Civil war. The influence of the war was so strong, that he felt hate to communism and those feelings he demonstrates in Animal farm. He demonstrates the irony of pigs’ actions that do the opposite of what the mayor ordered them to do. He sows pigs as self-serving. 
Explanation:
Pigs indulge many luxury things, even though they criticized men: 
"<em>And remember also that in fighting against Man we must not come to resemble him. Even when you have conquered him, do not adopt his vices. No animal must ever live in a house, or sleep in a bed, or wear clothes, or drink alcohol, or smoke tobacco, or touch money, or engage in trade..."</em>