As photosynthesis is a process that requires sunlight, the rate of this process will be 0 in a room without any light.
However, even if the dark room has very little light, it may still not be enough for photosynthesis to occur. This process requires certain levels of sunlight.
Plate tectonics is the theory that the earth's crust(lithosphere) is separated into plates and that they glide over the mantle(the layer underneath the lithosphere).