Answer:
the food chain is more stable and lasting
Explanation:
where there is an ecosystem with lots of plants and animals you get a stable food chain. where there are fewer plants and animals most animals have to compete with other animals for food.
Well a mutation is like a change in the DNA and so if there was a mutation in the antártica fish, something in their genes would change. If that mutation has a positive effect on it, then that mutation would be passed down to the generations of fish, helping that fish with its survival or something