The type of pronoun used in the above sentence is a RELATIVE PRONOUN.
The relative pronoun is found in the beginning of the adjective phrase. The adjective phrase describes the noun.
In the above sentence the adjective phrase is: WHICH IS SOMETIMES CALLED THE RED PLANET.
It describes the noun MARS.
The relative pronoun used is WHICH.
        
                    
             
        
        
        
Answer:  It explains what allowed him to split himself in two and why he can no longer continue to do so.
 
        
                    
             
        
        
        
Answer:
Cause and effect 
Explanation:
The excerpt structure clearly shows cause and effect relationship as the sentence follows a pattern showing the reason or cause of a certain phenomen and the its effect. With the author highlighting the reason they had to ride segregated buses as being their inability to afford a car. Chronological lists events in order of occurrence. While problem and solution highlights an issue and it is followed up by the cure or remedy. 
 
        
             
        
        
        
Brutus, he killed Caesar because of Caesar's ambition.
Hope this helps. - M