Question

Brown hydra is:
A. Hydra vulgaris
B. Hydra viridis
C. Hydra fusca
D. Hydra gangeticus

Answer 1

Hint: Hydra are a family of fresh-water organisms, classified under the phylum-Cnidaria. They have tiny, tube-shaped bodies that contain several tentacles at one end. While various species have classified, two of the most characteristic species include: Hydra oligactis (brown hydra) and Hydra viridissima (green hydra).

Complete answer:Scientific classification of brown hydra is; kingdom-Animalia, phylum-Cnidaria, class-Hydrozoa, order-Anthoathecata. Brown hydra present in the northern tropical zones. It is located in tranquil waters from early Spring to late Autumn. Their bodies are small, about 10-20mm in length and also quite simple, composed of two cellular layers around a central cavity. At the end of the cavity, the hydra's body gives away tentacles which surround the hydras. They usually secure themselves at hard surfaces including stones and pits of plants. There the hydra remains for food, its tentacles stretching up to three folds of the length of its body in search of prey like crustaceans, insects and even small fish. Many of the hydras trapping ability lies in those tentacles, which are provided with little projectiles, cellular capsules called nematocysts. The cylindrical body of the nematocyst is attached to a long thread which conserves different functions. One type of nematocyst is clipped with the thread, designed to wind around the Hydrus prey. The other kind of nematocyst has an opening at the tip which allows it to puncture the surface of Hydrus prey to inject a neurotoxin. When prey brushes up, begins the Hydrus tentacles, the nematocysts release quickly, this experience is around 5,410,000g's of force in 700ns of time, that speed helps the thread of nematocyst to catch its prey. Daphnia is one of the foods for brown hydra. Brown hydra have other names like hydra oligactis, hydra fusca.
Hence, from the above discussion, we can resolve that the right answer is Option-C Hydra fusca.

Note:During the feeding the mouth of hydra is sealed by the rest of the body in a continuous sheet of cells. Thus, to eat, hydra essentially has to tear a hole, open its body to let the prey in which it does by transferring neuronal signals that expand the mouth apart.