How does a Hydra reproduce? Explain with the help of labeled diagrams.

Hydra reproduces primarily through asexual budding when environmental conditions are favorable, though it can also reproduce sexually under stress conditions. During asexual reproduction, a small outgrowth or bud emerges from the parent Hydra's body wall, typically in the middle region of the organism. This bud initially appears as a small protrusion of the body column, containing extensions of both the outer ectoderm and inner endoderm layers along with the central gastrovascular cavity. As the bud grows over several days, it develops its own set of tentacles around a mouth opening at its distal end, essentially forming a miniature but complete Hydra while still attached to the parent.

The developing bud receives nutrients from the parent through the continuous gastrovascular cavity connecting them. Once the bud reaches sufficient size and develops all necessary structures—tentacles for prey capture, mouth for ingestion, functioning body column with contractile cells, and basal disc for attachment—a constriction forms at the connection point between parent and bud. This constriction deepens until the young Hydra detaches completely, becoming an independent organism genetically identical to its parent. A single Hydra can produce multiple buds simultaneously when food is abundant, enabling rapid population expansion. Under unfavorable conditions such as cold temperatures or food scarcity, Hydra switches to sexual reproduction, developing temporary gonads (testes or ovaries) on its body wall that produce gametes, leading to fertilization and formation of a resistant cyst that can survive harsh conditions before developing into a new Hydra when conditions improve. This reproductive flexibility allows Hydra to optimize its strategy based on environmental circumstances.