Question

Which of these phenomena is found in Hydra?
A. Metamerism
B. Metabolism
C. Metamorphosis
D. Sexual dimorphism

Answer 1

Hint: Hydra belongs to phylum cnidaria and class hydrozoa. Hydra is a genus which includes small freshwater organisms. They are native to the temperate and tropical region. Hydra, Phylum name Cnidaria is derived from the cnidoblast or cnidocytes which contain the stinging capsule or nematocysts present on the tentacles of the body.

Complete answer:
- In some Animals, the body is externally and internally divided into segments with the serial repetition of at least some organs. For example in earthworm, the body shows this pattern called metameric segmentation and the phenomenon is called metamerism. This phenomenon is absent in hydra.
- Metabolism is a characteristic feature of life. All living organisms are made of chemicals. This chemical, small and big, belongs to various classes. Are constantly being made and changed into some other biomolecules. These conversions are a chemical reaction of metabolic reactions. There are thousands of metabolic reactions occurring simultaneously inside all living organisms be it multicellular or unicellular. All plants, animals, fungi and microbes exhibit metabolism. The sum total of all the chemical reactions occurring in our body is metabolism. As it is present in all organisms Hydra also has metabolism.
- Metamorphosis is the process by which there are different stages of development which occur in insects. This is also absent in hydra.
- Sexual dimorphism is the condition in which two Sexes of the same species exhibit different characteristics. Hydra do not show sexual dimorphism.

So, the correct answer is (B).

Note: Cnidoblast are used for Anchorage, defence and for the capture of Prey. This is one of the characteristic organs of hydra.