Medusa and polyp - question

[felicious]

I am working on a biology I homework assignment, and am wavering on my answer to a particular question.
A medusa typically has more specialized organs for movement and response than a polyp does. Why might this be the case? I'm taking into consideration how the lifestyle of a medusa differs from that of most polyps...
Any help is appreciated.

Thank you.

[mith]

Hint, reproduction.

[Darby]

I think my hint would be sessile vs mobile - just follow up your initial instincts.