Question

Stereogastrula of Hydra is called so because of its

• A. Solid nature
• B. Two layers
• C. Encapsulation
• D. Hollow nature

Answer 1

Answer: (A)

Solid nature

In Hydra, after fertilisation, the zygote undergoes complete cleavage and a hollow blastula is formed which changes into a solid stereogastrula whose ectodermal cells acquire cilia. This stereogastrula changes into free-swimming planula (larva). Planula attaches itself to the hard substrata and transforms into the young Hydra through metamorphosis. Therefore, the correct answer is option A.