The words or phrase that should be added to the paragraph to increase its cohesion are:
The compulsory study of mathematics for high school students for four years will enable the students have a higher intellectual and thinking capacity.
This is because, solving mathematics requires a high rate of thinking fast. This helps the students build a high thinking faculty.
Therefore, it is very important for everyone to study mathematics in highschool irrespective of the profession they choose in order to increase their intellectual capacity.
