In context, which of the following revisions is necessary in sentence 1 (reproduced below)?

Heart of Darkness by Joseph Conrad may be a narrative about colonization, revealing its drawbacks and corruption, it may also be understood as a journey into the depths of one's psyche, if taken at a symbolic level

Direction for questions 7 to 12: The following passage is an early draft of an essay. Some parts of the passage need to be rewritten. Read the passage and select the best answers for the questions that follow. Some questions are about particular sentences or parts of sentences and ask you to improve sentence structure or word choice. Other questions ask you to consider organization and development. In choosing answers, follow the requirements of standard written English.

 Spiritual Journey in Heart of Darkness

(1) Heart of Darkness by Joseph Conrad may be a narrative about colonization, revealing its drawbacks and corruption, it may also be understood as a journey into the depths of one’s psyche, if taken at a symbolic level.

(2) At the beginning of the novel, the reader is informed that Marlow is a ‘wanderer’ and was ‘not typical’ contrary to stay–at-home–minded seamen.(3) He has no home, in a psychological sense of the word.  (4) He simply “follows the sea”.  (5) This may evoke an interpretation that the man is disturbed, that he attempts to find out about the secrets of his soul, to get to know himself. (6) Since boyhood he had been interested in unexplored lands and especially in a long winding snake-like river with the “head” in the sea and “tail” plunging deeply into the land, which, as Marlow admits, “charmed” him.  (7)  This image resembles a map of a journey from the dark lands of the soul, the unconstrained, uncivilized core, which may be called a Freudian Id, towards light, that is Superego.(8)  Marlow desires to follow this path in the opposite direction to explore the depths of himself.

(9) If it is a dark Id, then Superego is presented as the civilized world, full of light, knowledge, awareness of the self. (10)  The light came upon the gloom of London with Roman conquest. (11) An orderly and disciplined society has been introduced by force formed by the ravages.  (12)The Roman conquest symbolizes the eternal battle between the Id and the Superego, the latter always struggling to impose rules on the former.  (13)  This is what is taking place in Congo.  (14)  The aim of the colonists is to bring Christianity to the black people, but in the end it turns out that it is not the civilization which wins, but the Id. (15) It rots the soul with corruption, stealing money from the natives. (16)  When there is no watch from the society over one’s doings, one can do anything they please, like Kurtz, whom Id overtook completel