germination
A seed is a reproductive structure that contains an embryo and a food supply, called endosperm. Both the embryo and endosperm are enclosed within a tough outer coating, called a hull or shell . You can see these parts of a seed in Figure below . An embryo is a zygote that has already started to develop and grow. Early growth and development of a plant embryo inside a seed is called germination . The seed protects and nourishes the embryo and gives it a huge head start in the "race" of life.