Which form in Phylum $Cnidaria$ is free-swimming?

In $Hydra$,undigested food and nitrogenous waste products are removed through:

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

It is a common cavity that performs both digestive and circulatory functions.

The colonial form found in Phylum $Coelenterata$ (Cnidaria) is:

Write the characteristics of Phylum Coelenterata (Cnidaria).