Hello. You did not inform which story you are referring to, which will leave my answer a little inaccurate, but I will give you a general answer that I believe can help you and I hope it really helps.
The scenery situalizes the story, shows an environment that is essential for the portrait that the screenwriter is waiting for the developed plot. That's because, the scenario is a living element in the plot, his ability to environmentalize the story. This environmentalization defines which culture the story is stabilized in, allowing the characters' positions to be understood. An example of this can be seen when the screenwriter uses a rural setting and the characters and the story are shaped with elements from rural regions, which totally differ from a scenario in an urban city.
The difference between sharks and fishes is based on their bones, skeletons, and skin texture and body shape. Key difference: Sharks are a type of fish.
