Read the passage below. Prior to the 1970s, scientists thought that new neurons could not be generated in adult brains. In the 1970s, Dr. Goldman and Dr. Nottbohm discovered that hormones injected in adult songbirds could cause female songbirds to develop new neurons. Which statement best exemplifies the scientific principle that was involved in this case? New experiments do not affect science because science remains constant. New experiments can affect future scientific explanations. New experiments can affect previous scientific explanations. New experiments yield untrustworthy data and should be carefully considered.