Problem with paragraph 1:
Get rid of the passive voice sentence as it reads somewhat unclear.
Problem with paragraph 2:
Focus on the positive rather than the negative
Problem with paragraph 3:
Change the word ´caught´
Problem with paragraph 4:
I´ve rewritten this one for a better flow
Although money seems to be a powerful incentive, I’m not sure that it is enough to tempt young people to study something they are not interested in. Young people are idealistic and want to make a difference in the world. That’s why I strongly believe that advertising is the most effective way to encourage people to study science – we can present role models in the world of science and make the field seem both cool and important.
Now, although my version has a nice flow, it doesn’t really have a lot of the advanced structures that really grab the examiners’ attention. If I had ten minutes left in the exam I’d definitely go back and make sure I had some: