What is the weight of a watermelon seed?
Seed bearing plants propagate sexually (for the most part). Seedless plants propagate asexually (offspring arise from a single parent). Seedless watermelon plants are grown from seed produced sexually (two parents). The actual seedless watermelon is produced by a seedless watermelon plant flower that is fertilized by bees carrying pollen from another parent. The resulting seedless watermelon has vestigial seeds which are sterile. Is that complicated enough?