Final answer:
The most significant source of fiber in a cereal bar is rolled oats, cranberries, and almonds.
Step-by-step explanation:
The most significant source of fiber in a cereal bar is rolled oats, cranberries, and almonds. Rolled oats are whole grains and are a rich source of dietary fiber. They are often used as a base in cereal bars to provide a chewy texture and fiber content. Cranberries and almonds also contribute to the fiber content and add flavor and texture to the bar.