Question

The group to which jellyfish belongs is
A) Coelenterate
B) Mollusca
C) Arthropoda
D) Pisces

Answer 1

Hint:Jellyfish are known to be free swimming marine animals that comprise umbrellas like bells and tentacles that help them in their locomotion. They are large and colourful and found mostly in the coastal zones.

Complete answer:
Jellyfish belong to the Cnidaria, which along with Ctenophora comprises Coelenterate. Coelenterates are classified as having hollow body cavities as well as simple tissue organization with only two layers of cells. Mollusca have a unique body structure known as mantle, that contains a cavity that is used for breathing and excretion. Arthropods are known to consist of an exoskeleton, a segmented body and paired appendages. Pisces have an elongated body with gills, lacking limbs. The most distinctive feature of jellyfish is their umbrella shaped bell which consists of a transparent jelly like substance known as mesoglea and presence of a mouth that also serves as the anus. Most of them do not have a well developed respiratory or circulatory system, oxygen enters by diffusion through the epidermis. The tentacles comprise nematocysts that provide the sting. The size of the jellyfish varies from one millimeter up to two metres in with respect to bell height and diameter. Jellyfish are known to have complex life cycles including both sexual and asexual phases. A clear idea about their lifespan is not known yet as they occupy benthic zones which are difficult to reach.

Hence the correct answer is option (A) Coelenterate.

Note:Jellyfishes are found everywhere in the world and they have multiple uses. They are consumed by humans in a few cultures since they are found to be rich in proteins with low calorie. They are also used in research due to their bioluminescence property.