To keep the poor from rebelling, the ancient roman government began a program sometimes a. grain and games b. bread and circuses c. wheat and play d. food and carnivals

it should be c, women were allowed to vote in all states because federal law supersedes state law.

"states can make their own laws, as long as they don't contradict what the federal law states. the states do not have the authority to pass a law that negates a federal law." -google

i believe the answer is:   psychological  experiment

in this experiment, wilhelm wundt became the first person that implement scientific method in analyzing the pyschological phenomenon.

due to this result, wilhelm wundt also able to make psychology to be acknowledged as a separate scientific field from biology.