Question

which part of the flower becomes the seed and the fruit

Answer 1

A fruit is a ripened ovary. After the ovule in an ovary is fertilized in a process known as pollination, the ovary begins to ripen. The ovule develops into a seed and the ovary wall pericarp may become fleshy (as in berries or drupes), or form a hard outer covering (as in nuts). In some cases, the sepals, petals and/or stamens and style of the flower fall off. Fruit development continues until the seeds have matured. With some multiseeded fruits the extent to which the flesh develops is proportional to the number of fertilized ovules.