You have to follow the research tree. Click on subject you want to research. This will send subject to 'ready' box. Read the bottom line(requirements) of description box and this will tell you what prerequisites are required. If no requirements(may have them already), requirement box will not show, as you already have met them. The 'allows production/research' box will be last or bottom of list. Hope this helped.
17 Nov 2015, 14:42
