Seeds have different internal structures. We want students to be aware of structures such as the seed coat, embryo, and cotyledons. Students compare these structures across several seed types and investigate the functions of these structures. Students observe and document the emergence and duration of individual seed structures such as roots and leaves.

Before working closely with seeds, students often have only a basic sense of their internal structure. For example, there is some awareness that seeds have a protective layer and and at least one, embryo-like internal features. In some cases, students are aware of the cotyledon and its nutritive function in the seed. After working with soaked seeds (e.g., giant lima beans) and germinating seeds in plastic bags and on water agar, students become familiar with more internal structures, and in drawings, will represent the embryo (or "baby plant"), roots, root hairs, cotyledon (often referred to as "food"), and the seed coat. At this stage, students have developed a prototypical model of a seed and do not differentiate between seeds. With an understanding of basic seed structures and the germination process, students can begin to think about structural variation in seeds and how these differences are tied to function.