Hi,
First, you should post all IELTS essays into Writing Feedback forum. (I moved your essay from "Undgraduate" to "Writing Feedback" ) :) This would help you earn more relevant feedbacks :)
Television is populated by all people from child to adults
Television is very popular among people of all ages, however, Should children learn efficiently by watching television regularly both in school and at home?
.... this should be a new sentence.
Therefore, I don't agree with this opinion.
Watching TV can learn efficiently is senselessness
... this is grammatically wrong;
Watching TV helps children learn efficiently is a statement without much sense. .... however, this sentence does not provide a reason to justify your opinion. Therefore, you should remove this line from the essay. You should start with the second sentence though it needs corrections;
First of all, young students whom they cannot self-controlled by themselves
First, TV can make young children addicted to watching its programs because they lack enough maturity to control themselves.