A 300N uniform rectangular sign 4m w ide is suspended from a horizontal, 5m-lo ng rod, so that the sign's right edge is lined up with the rods right end. The we ight of the rod is 80N. The left end of the rod is \

When can a theory be modified if a new type of technology allows for new observations that raise new questions? a-immediately, while the questions about the theory are being asked b-after new hypotheses related to the theory are tested in experiments c-only after the new observations disprove all parts of the theory d-while scientists begin to think about how the theory could improve