Mention 2 famous scientists in your country?

Well, I guess, I would have to say that there are 2 famous scientists in Korea = (You have to change this. It's already the point of the question so it's unnecessary to say it again.) 
First off, Doc, 우장춘.
One of the most famous scientists in the field of genetic engineering
He discovered genetically modified food such as super watermelon and tomatoes.
And the foods also produce regardless of season.
What’ more, DOC, 채연석 = ()
He also very popular person related to outer space sector. = 
DOC, 채연석 is also very popular person in the outer space sector.
He has been conducted researches about artificial satellite.
He also lead to spacecraft production technology in Korea.

Why should we invest more in research?

Well, I guess, I would have to say that there are probably a number of factors involved here.
Firstly, studies play an essential role in developing a nation’s industry.
This is because, most studies can contribute to the development of science and technology.
Secondly, it is a great way to prevent people from various disasters. = Secondly, it is a great way to prevent various disasters.
The reason for this is that a lot of policies have implemented based on the consequences of research. = (I'm not sure what this means)
As a result, it can lead to improve our quality of life and raise the level of nation to developed country.

What is the single important invention in your country?

Well, I guess, what I think is that microwave oven. = I think microwave oven is  the single important invention ever made.
This is because, it is a very beneficial electronics to cook easily. = This is because, it helps us cook food easily and fast.
In modern society, most people lead very busy lives due to heavy work and studies.
As a result, it provides us with a convenient life to prepare our meals.