Mango grows from a seed. Seeds are the reproductive structures of plants that contain the embryo of a new plant. When a mango seed is planted in the soil, it germinates and starts to grow into a mango tree. The seed provides the necessary nutrients and genetic material for the development of the new plant. Through the process of germination, the seed sprouts and forms roots, stems, leaves, and eventually flowers, which then produce fruits like mangoes. Therefore, the correct answer is "Seed."