Hi andika08.
It seems that you used many reduced forms of adjective clause and adverbial clause. However, it is acceptable in the IELTS test.
But, I think it would be better if you variate into the normal form of the clause.1.
when having been eposed to several ...
Do you mean exposed?2. The reason is
in that this subject
containcontainsa different material
s that not many ...
For example,
the survey from University of (...) who learn about art
spendingspend much time than in the
otherssubjectother subjects .
... learning this subject
(,) children cannot focus on
others subjectother subjects .
This is because
in this subject provide
ana practical experiment that make them
would learn
manymuch new knowledge.
... project and find new discovery
waswere getting the
great achievement and new experience.
... this practical subject
(,) the children (...) to face the next
stages of life.
Suggestion:You can add your personal statements in the conclusion to emphasise your state of this opinion.
Goodluck.