Which type of reproduction involves the formation of a gemmule?

Gemmules are structures formed by certain organisms as a means of asexual reproduction. This process allows the organism to survive unfavorable conditions by creating a resistant structure that can give rise to a new individual when conditions improve. The formation of gemmules primarily occurs in certain sponges, which can produce these encapsulated groups of cells that are capable of developing into new sponges.

Asexual reproduction is characterized by the production of offspring without the involvement of gametes, meaning that the genetic material comes from a single parent. Gemmules specifically exemplify this type of reproduction, as they enable the organism to reproduce without the need for sexual reproduction mechanisms, such as the fusion of male and female gametes.

In contrast, sexual reproduction involves the combination of genetic material from two parents, thus is not relevant in this context. Binary fission and budding are forms of asexual reproduction, but they do not specifically involve gemmules. Binary fission is typically seen in unicellular organisms, while budding usually refers to the growth of a new individual from a part of the parent organism, without the formation of a specialized resistant structure like a gemmule.