Directions: Choose the correct option to fill in the blanks.

Man’s deepest _____, after all, is to understand himself and his place in the universe - to _____ his own nature as a living organism and the interactions between heredity and environment that shape the development of his body and mind.

This sentence emphasizes on man’s urge to understand the Universe around him and to understand his role in nature. Thus, 'urge' and 'inquietude' (restlessness, anxiety) both fit our predictions for the first blank. But to 'err' is to be wrong or mistaken whereas 'fathom' is to interpret or understand, which therefore fits our prediction for the second blank. Hence, (1) is the answer.