What is the error in sentence 5?

Directions for the question:

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 answer for the question that follows. Keep in mind that some questions are about particular sentences or parts of sentences and ask you to improve sentence structure or word choice. Other questions ask to consider organization and development. In choosing the answer, follow the requirements of standard written English.

(1) Under the present system of mass education by classes so much stress is laid on teaching and so little on active learning. (2) The child is not encouraged to discover his own powers, thus losing intellectual independence and all capacity to judge for himself. (3) The over-taught child is the advertising-believing propaganda–swallowing, demagogue–led man. (4) Such is the man who makes modern democracy the force it is. (5) Moreover, lessons in class leave him mainly unoccupied. (6) He has to be coerced into learning what does not interest him and the information acquired mechanically is rapidly forgotten. (7) Quite naturally, the child, being bored and unoccupied, is also mischievous. (8) A strict external discipline becomes necessary unless there is to be chaos and pandemonium. (9) The child learns to obey, not to control himself. (10) He loses moral as well as intellectual independence. (11) Such are the main defects in the current system of mass education. (12) Many others could be mentioned but there are defects in detail. (13) We need a new system of universal education of the same kind as that proved so successful in the training of detectives and infants, but modified so as to be suitable for older boys and girls. (14) We need a system of individual education.