Thus an experiment is suggested. We then do the experiment and feed the aquatic plant seeds to birds, collect the seeds as they pass through the digestive tract and determine their viability. We can begin to accept the hypothesis. Thus the answer to one question leads to others. Eventually a body of evidence begins to form around a general topic that enables the formulation of a theory.
Scientists use the word theory differently from the general public.
A scientific theory is something that has a massive body of evidence to support it. Think of atomic theory, cell theory and evolutionary theory.