The function of cnidoblasts in Coelenterata is ..........

Hydra is

$A$ diffused nervous system is observed in . . . . . . .

The presence of cnidoblasts is a characteristic feature of which phylum?

Identify the correct features for $Medusa$ and $Polyp$ forms in Phylum $Coelenterata$ (Cnidaria) from the given list:
$I$ - $Sessile$
$II$ - $Umbrella-shaped$
$III$ - $Free-swimming$
$IV$ - $Produced$ $by$ $asexual$ $reproduction$
$V$ - $Cylindrical$
$VI$ - $Produced$ $by$ $sexual$ $reproduction$
$Medusa$ $\quad\quad$ $Polyp$

The symmetry found in the phylum $Cnidaria$ is: