Mrs. Stevens asked four of her students to research how running water affects the shape of a stream over time. To find the answer: Morgan performed an internet search, read books in the school library, and looked at articles in scientific journals. Casey built a model of a stream and performed controlled experiments. Maria observed several different streams near her house for a few hours. Jamal interviewed local scientists who routinely study stream flows and shapes. Which student's research most likely produced the weakest scientific evidence?