Question

Free swimming larva of Obelia is
A) Planula
B) Amphiblastula
C) Stereo Gastrula
D) Hydrotube

Answer 1

Hint:Obelia (also called sea fur) is an aquatic animal found in both marine and freshwater bodies. It is a genus of hydrozoans from the phylum Cnidaria and has both polyp and medusa stages in its life cycle.

Complete answer:
Let us look at each option one by one.
Planula is the ciliated, bilaterally symmetrical, flattened, free swimming larva of organisms in the phylum Cnidaria. Obelia also belongs to this phylum. Therefore, this is the correct option.
Amphiblastula is the free swimming larva of certain sponges. Obelia is not a sponge. Therefore, this option is incorrect.
Stereogastrula also known as Parenchymula larva belongs to organisms of the phylum Porifera composed of sponges. Obelia belongs to the phylum Cnidaria. Therefore, this option is incorrect.
HYDROTUBE is the abbreviation for "Reduction of carbon dioxide (CO2)-impact by reduction of weight achieved by bending and HYDROforming of steel and aluminium TUBular parts for body and chassis applications". This is not related to Obelia at all. Therefore, this option is incorrect.

Thus, the correct answer is option (A) Planula.

Note:Obelia is a sexually reproducing organism. When in the medusa stage, the male and the female medusa produce sperms and ovum respectively which are released into the water where fertilization takes place.