If you are the most intelligent person ever born

I think it would be hard to answer, because with my current intelligence level I cannot even think of higher and more academic areas and higher ideas. But I think I'd work on health projects, like finding a cure for cancer and other uncurable diseases.

multi purpose fuel that would replace oil and could be used to power all types of vehicles, electricity,and all that needs energy without producing harmful effects in the environment and could help clean up pollution of our surroundings.

I would focus on health related things and find a new cure for cancer. Today the common treatments are surgery, radiation therapy and chemotherapy, but radiation therapy and chemotherapy have many side effects and the treatment that I would invent would be a treatment without any side effects and it would also be a treatment that would eliminate the need of surgery. Today two things affect your chance of survival - the type of cancer and the stage of the cancer. If you are diagnosed in a late stage it is often difficult to cure the disease. I would like to invent a treatment that would be able to cure cancer in the late stages as well.

I think my research would be about the environment, since it needs repair, like now. I would build whatever that is needed to be built to stop global warming/climate change, a shield or something or radiation..Adn also a solvent to make garbage disappear, fast.

i would develop some superficial machines to take on the aliens and destroy them and utilise their resources

Well I too am not that smart as well but I can always try to be reasonable here. I think i would choose to invent something that will be better than money and everyone could afford it and things would just change for all. There is abundance of everything and even if all of us are rich, things won't finish on earth. I would like to find a substitute to money. Thanks for sharing and have a wonderful day ahead.