Question

how does the ovary form a fruit

Answer 1

After fertilization i.e. after the fusion of male (pollen) and female (ovule) gametes. The ovary grows and gives rise to the fruit, while the other structures of the flower fall down. Thus, the fruit is a ripened ovary. The ovules present inside the ovary develop into a seed. Seeds contain an embryo, which is protected by the seed coat.