A seed is a small embryonic plant enclosed inside a seed coat. It is the ripened and fertilised ovule of gymnospermic and angiospermic plants. The embryo is an undeveloped plant inside a seed from which a new plant develops. All seeds do not have the same size, shape and colour. Plant embryos in seeds have structures called cotyledons. A cotyledon is the central portion of a seed embryo to which the epicotyls- the immature shoot, and the radicle- the immature roots, are attached. Plants are classified according to the number of cotyledons present in the embryo. If the embryo has one cotyledon (monocotyledon) it is a monocot plant, and if there are two cotyledons (dicotyledon), it is a dicot plant.
This video explains how to identify the different parts of an embryo of dicot seeds- pea, gram and bean.