Following are some of the events that occur during the development of animals.The structures formed during the event X are

Explanation

The correct answer is Option B: blastomeres. Blastomeres are the cells that result from the cleavage of the zygote, which is one of the earliest stages of embryonic development. During cleavage, the single-celled zygote divides into multiple smaller cells known as blastomeres.Option A: somites are structures related to later development stages involved in forming vertebra and muscle organization, not the initial cell divisions. Option C: epiblast and hypoblast are layers formed during gastrulation, which occurs after cleavage. Option D: neural groove and neurocoel are structures formed during neurulation, another later stage of development.