In my opinion, the most pressing problem would have to be the management of poverty. South America is a huge continent with lots of potential for its people, but it needs some firm leadership.
"management of poverty" -- what does that mean? You want to manage things so everyone is equally poverty-stricken??
Land is very unevenly distributed and there are mainly 2 social categories: Rich and Poor, poor being the majority with a tiny percentage of people you can call "Middle Class". This sentence seems to indicate that the rest of your answer will concentrate on the distribution of land ... but then ...
As for a solution, the government should have a set goal and while working on things to better the tourism aspect of the country, they should have equal importance for the poor and do more that would benefit them. ... you jump into tourism, but make no connection between this and land distribution ... huh?
They can distribute land more efficiently, take charge of extra land and then evenly distribute it to the poor so that they may have the opportunity to feed their families while still being able to make a profit.
This is closer, but without many details. Just how does a government (and there are several in SA, right? "take charge of extra land" and then distribute it? Have lotteries? or what?
Education for the under-privileged children should be the top priority, because their education is what is going to help them have a successful future.
Another topic introduced??
Housing should be administered for the homeless to eradicate the poverty in slums.
And still another?
Your ideas aren't bad ideas; they are just not organized and expanded well enough. You are all over the place. The question asks for "the single most pressing problem" -- and you are briefly mentioning five.
How can you reorganize and revise this so that you have a cohesive answer to the question, and yet include sufficient details that you aren't just painting with a too-wide brush?
When you learn some manners and also learn that South America is NOT a country, then re-think this and try again.
South America "includes twelve independent countries—Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Guyana, Paraguay, Peru, Suriname, Uruguay, and Venezuela"* -- how will you answer this question AND deal with twelve different geographic regions and independent governments?