Question

Hydra shows locomotion by:
A. Somersaulting and looping
B. Gliding and climbing
C. Walking, floating, and swimming
D. All of the above

Answer 1

Hint: Hydra belongs to the phylum Coelenterata. The locomotion in hydra is by various means that are by somersaulting and looping, gliding and climbing, walking, floating, and swimming. Hydra has several methods of locomotion.

Complete answer:
> Hydra: it is a small freshwater animal belonging to the phylum Coelenterata. It has a polyp form of a body. It is a sessile containing basal disc and tentacles used at the time for locomotion and feeding. The tentacles consist of nematocysts.
Locomotion in hydra:
> Looping- hydra moves from one place to another by looping. While looping, it bends its body from its standing position and attaches to the substratum with the help of its tentacles containing nematocysts. It then releases the attachment at the basal disc and moves its free end to a new site. The animal then stands up by making free its tentacles.
> Somersaulting- it is another method of locomotion in hydra. It is a little modification in looping locomotion. In this, the Hydra fixes itself on the substratum with the help of hypostome end and then shifts the attachment of the basal disc. The basal disc is then rotated itself 180° and fixes to a new position. The hypostome is again raised and the hydra moves to a new position.
> Gliding- Hydra may glide along the substratum by the pseudopodia action of the basal disc cells.
> Floating- Hydra produces a bubble of gas, which helps the animal to float on the surface of the water. The animal is passively carried from one place to another by the water current.
Climbing- hydra climbs by attaching its long tentacles to some object. It then releases the foot, contracts the tentacles, and thus gets lifted to the object.
> Swimming- hydra swims in water by the undulating wave-like movements of the body.

The correct answer for the above question is option (D) i.e. All of the above.

Note: Some points to keep in mind are listed below:
The organs helping in locomotion in hydra are basal discs and tentacles.
The basal disc is used for the attachment at the substratum and tentacles used at the time for locomotion and feeding.