Question

The gastrovascular cavity of hydra provides for
(A) Digestion and storage
(B) Storage and circulation
(C) Excretion and storage
(D) Digestion and circulation

Answer 1

Hint: Hydra are the freshwater organisms that are very small tube-like organisms. They feed on the insect larvae or the fleas present in the freshwater like ponds, lakes, slow flowing river water etc. It belongs to the phylum cnidaria and the class hydrozoa. They follow the asexual reproduction to produce its offspring,

Complete answer:
In the hydra, the polyp-like body is surrounded by the tentacles. These organisms appear as the globular and the shorter. These organisms possess the central cavity body and this acts as the gastrovascular cavity. This cavity is called coelenteron. This has the single opening and it performs the digestion and the circulation. Surrounding this the buds starts to grow. The hydra is surrounded by the two layers as ectoderm and the endoderm. The reproductive organs of the testis and the ovary are present in the ectoderm.

It also contains the gland cells that secrete the sticky substances and the gas bubbles. These are carnivorous in nature since they feed annelids, copepods and the cladocerans etc. They follow the process of contraction prey which means these organisms contract and expand its body in order to capture the prey. After that it throws the prey in the cavity and it gets digested by the digestive enzymes secreted by the gastrodermis or endodermis. After the digestion, the nutrients get circulated and they do not have a well-developed circulatory system.

Hence the correct answer is OPTION(D)

Note: The hydra follows the asexual reproduction. In this the buds are developed on the basal part and it remains there until it is fully developed with the body and the tentacle. After that it detaches from the body of its parent and lives independently.