Answer:
Gastrovascular Cavity
Explanation:
Hydra is commonly found in freshwater ponds and ditches as solitary organisms, in underside of aquatic leaves and lily pads in cool,clean freshwater pools and streams. It has a *Cylindrical body shape*.
Hydra possesses an internal body cavity, the *Gastrovascular cavity *,lined by gastrodermis and has a single opening,the mouth,which serves as an anus.
The Gastrovascular cavity of Hydra is a site for *digestion and nutrient distribution*,and also serves as anus.
Kelp is very sensitive to temperature change. Placing the plant near the window and exposing it to direct sunlight will result in continuous warming of the water in which the kelp plant is growing. Research has shown that kelp plant degrades very quickly when temperature increases due to tissue loss.