The animals of this phylum exhibit tissue-level organization.

In which of the following is radial symmetry observed?

Which of the following cells are present only in the epidermis of Hydra?
$(A)$ Interstitial cells
$(B)$ Cnidoblasts
$(C)$ Sensory cells
$(D)$ Germ cells

Cnidoblasts are present in .......

The body cavity of $Hydra$ is called:

In $Hydra$,egestion of undigested food and excretion of nitrogenous wastes occur through