Simplify the following text for a Grade 12 native English-speaking person.
Original: Medusae have a radially symmetric , umbrella-shaped body called a bell , which is usually supplied with marginal tentacles - fringe-like protrusions from the bell 's border that capture prey .
Simplified: Medusae have a radially symmetric , umbrella-shaped body called a bell , which is usually supplied with marginal tentacles that capture prey .