Questions about genetics

Lately we've been doing presentations about genetics in our Scientific Culture class. I've been working with Leire and our theme was the Human Genome. We had to search for a video about it and then explain it in front of the class. Now, we've to make questions for a exam we're doing.
Here you've our questions:

 1.  How many years did the scientists need to sequence the first human genome?  
    
     a)  1 year 
     b)  8 decades   

     c)  17 years  

     d)  2 decades   

2.  Genes are made up of…

     a)  Tissues   

     b)  DNA    

     c)  Cells  

     d)  Organs

3.  When does the A, T, G, C sequence stick together?

    a)  When they are exactly the same    

    b)  When they are exact opposite    

    c)  Never

    d)  

4.  What allows us to read each piece of DNA?

    a)  Seeing the order of the colors  
    b)  The order of the letters  
    c)  Scientists can´t read them
    d) Computer programmes