Question

Male gonads in Hydra are found
A. In lower half of the body
B. Near the hypostome
C. Anywhere on the body
D. Exactly in the middle

Answer 1

Hint: Hydra is a fresh-water organism of the phylum Cnidaria and class Hydrozoa. They have a thin tubular body which can measure up to 10 mm and is capable of great contraction.

Complete Answer:
- Hydra is a diploblastic animal with radial symmetry. They are native to temperate and tropical regions. Their characteristic feature is the ability to regenerate and they do not age or deteriorate with age. Most of their body cells are stem cells that are capable of continuous division and differentiation into any cell type in their body.
- The mouth opens at the free end of the body with one to twelve mobile tentacles. Each tentacle has stinging cells, called cnidocytes, covered on it.
- Cnidocytes have a small bulb-like structure on them called the nematocysts, which has a coiled thread inside it. Exposure to prey will cause the nematocysts to release the thread-like structure which contains neurotoxins that can paralyze the prey.
- Respiration and excretion occur through diffusion from the body surface and larger excreta is discharged through the mouth. They are generally sedentary but move when they are hunting. They move by looping or somersaulting or by an amoeboid motion of their bases or by detaching from the substrate and floating away with the current.
- Reproduction in hydra occurs asexually by budding. Eggs and sperm are in separate gonads in the outer body. They usually have separate sexes but some are hermaphrodites. Testes or the male gonads are found in the distal or oral end of the body i.e. near the hypostomal region.

Hence, the correct option is option B, ‘near the hypostome’.

Note: Hydras are considered as immortal as they do not age. In the wild, they are destroyed by predators or by the chemicals in water.