Question 1
Estudiar:graduarse :: niñez:adolescenencia (estapa de la vida)
Study:graduate :: childhood: adolescence (stage of life)
After you study, you can graduate. After you go through childhood, you enter into adolescence.
Question 2
muerte:nacimiento :: divorciarse de: casarse con
death: birth :: divorce: marriage
Death and birth are opposites, just like divorce and marriage.
Question 3
muerte: morir :: nacimiento:nacer
death:to die :: birth:to be born
These are just different forms of the verb.
Question 4
pareja:amor :: amigos: amistad
couple:love :: friends: friendship
A couple is in love, while friends have friendship.
Question 5
juntos: separados :: divertirse: aburrirse
together: separated :: to have fun: to be bored
Together and separated are opposites. The opposite of having fun is being bored.