Amazon Rainforest are hot that is why it rains alot, but in order to survive the forest they willl have to evolve to suvive predators and to catch food since the heat increased, metal melted and a chemical mutated the animals. They will have to become bigger so they can outgrow predators so they can't be eaten. Being big is cool but not too cool when you are slow so the fins will have to get bigger fins so they will move faster in the river to catch prey faster and to escape big predators. Lastly they will have to get sharper teeth in order to chop though prey faster because pictue this you are a fish in the Amazon rainforest and then because the tempure rises the fish have thicker skin to block the heat it will be hard to rip that so you need to have sharper teeth.
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