Question

Strobilation occurs during the development of
a. Hydra
b. Obelia
c. Aurelia
d. Adamsia

Answer 1

Hint: Strobilation or transverse fission could also be a kind of agamogenesis consisting of the spontaneous transverse segmentation of the body. It's observed in certain cnidarians and helminths. This mode of reproduction is characterized by high offspring output, which, within the case of the parasitic tapeworms, is of great significance.

Complete answer:
The moon jellyfish is known as Aurelia aurita that reproduces both sexually and by strobilation. This latter process takes place during the colonial polyp stage and develops either polyps or juvenile Medusae called ephyra. Strobilation tends to take place at specific periods, typically early spring. As ephyra size remains constant regardless of the polyp size, larger polyps develop more numerous ephyrae.

Addition information –
Strobilation in cnidarians starts with preliminary morphological changes. Especially, the cnidarian's tentacles tend to be reabsorbed.
Neck-formation: The transverse constrictions appear near the upper extremity of the animal. A strobilating polyp is known as a strobila while the non-strobilating polyp is known as a scyphistoma or scyphopolyp.
Segmentation: The quantity of constriction sites increases and migrates down the linear measure, transforming the body into a sequence of disks. The fissures intensify until the initial body is split into equally spaced, separate segments. The oral end of the polyp turns out to be the oral end of the ephyra.
Metamorphosis: Neck-formation and segmentation are only separated for clarity purposes. In reality, the two actions are parallel, with segmentation to release new ephyrae occurring at the upper end while neck formation spreads further down the body. Usually, some of the animal remains adhered to the substrate and regenerates the body. So, the correct answer is ‘Aurelia’.

Note: Strobilation is successfully produced in laboratory setup by in-depth feeding and temperature lowering, and also by the effect of artificial compounds. In cestodes, the whole body aside from the highest and thus the neck undergoes strobilation continually, reflecting the crucial role reproduction plays within the parasitic mode of life.