The discovery of the atom and the genome project. From the atom we achieve spectacular knowledge: Kinetic(and otherwise) motion, fission, fusion(which if demonstrated on our planet will eliminate the need for any other source of power), and so much more. From the genome we gain the fundamental tools to evaluate ourselves in the deepest sense. We not only can trace our evolutionary background, but we can see down to the protein that provides the many traits we possess. A further understanding will render genetic problems things of the past.

I would put forth genetic engineering of crops and nuclear energy. These have changed the world, and will continue to do so. These technologies apply to space travel, exoplanet colonization, helping out third world countries and many, many more applications.

The first thing would be the wheel.

Without the wheel I don't think we would have accomplished very much else, although I don't know if the wheel is under the category 'science'.

I can't really pick the second one. I guess electricity .. but I don't know.

Id have to settle on the Higgs Boson. The molecular atom that could put the power of the universe in our very hands. i cant explain much about it but serach it up and find out its wonderous capalities for our future.

Liquid Prell ;)

Spray cheese in a can. And the awesome auger .

Science has invented mobile phones which are very useful.Every one uses mobile phones.Laptops which makes our work very easy.

Science has made hundreds of things like Television,Radio etc. which are useful as well as harmful.If we use them in correct way then they are not so harmful.

The Internet because it has opened a door for everyone in the world to communicate and seek knowledge.

The cure for Polio was magnificent.