Can someone help me in writing an essay?

You could spring off the current flu epidemic for starters. Science works hand in hand with medicine. Right now there is a lot of talk about "going green". It's a pretty hot topic and it might be easy to research. Science is also working much in the fields of conservation. What can we burn instead of oil? And things like that... Thanks.. now I will be thinking about this all day! :) Hope those thoughts help you get started somewhere!

You can consider medical advances that science has helped improve compared to the early methods that were difficult as well as more expensive.

If you're having a hard time on finding ideas, then you could just compare the state of living between now and... about 100 years ago. There are a lot of things to talk about regarding scientific research that benefited our existence. Of course, there are also a lot of things regarding scientific research that were a detriment to our existence but naming them is not a bad thing either. You can use them as examples on how NOT to use science in building a better world and draw a conclusion from there. Science/scientific research & development has a big part in shaping the world, after all. You'll get a lot to write about if you focus on that. Good luck! :D

Why not start with the viewpiont of feeding the world and getting fresh water to all the different countries. As in how science can help bild more efficient wells, irrigation sites and help with the developments needed in growing the food. Good Luck.

first thing coming to mind is advances in medical research ....offering cures, trying to to spread of diseases etc... Secondly ' communication' technology. Enabling easier, faster communication between people, exchange and availability of information to all. Thirdly ' alternative energy' : The world is running out of resources and we have to find other ways to produce electricity etc...Also links to ' healthier and greener energy. Thats it for now!