Can humans cause a imbalance in the food chain

Yes they can. Here are some examples;
Sharks eat the fish that are in the sea, but humans hunt and kill them. This can lead to imbalance, and an increased number of fish. idk

Yes, because if we cause one species to go extinct, it starts the domino effect. Example: One day, after the oceans slowly getting polluted of time, oil and trash float at the surface, clogging the fish and other creatures to suffocate. If the fish eats some toxic waste or garbage, and a pelican swoops down and takes the fish, later it eats it and is poisoned. The pelican is found later dead, from the horrible sickness. Over the world, fish and pelicans are dying, and the animals that eat the fish and the pelicans. I hope this helps

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