Although you are completing an engineering project, just make sure that it fits in a category's description. Ask for help if you are unsure. The bolded titles are indicating categories popular with engineering. They are hyperlinked and will take you to a more descriptive page.
Behavioral and Social Sciences (BEHA)
Biomedical and Health Sciences (BMED)
Cellular and Molecular Biology (CELL)
Computational Biology and Bioinformatics (CBIO)
Earth and Environmental Sciences (EAEV)
Energy: Sustainable Materials and Design (EGSD)
Environmental Engineering (ENEV)