Answer:
To answer this question, we must define the two key terms within this question, organism, and ecosystem.
Organism, by definition, is "one animal, plant, or single-cell".
Ecosystem, by definition, is a "community of organisms interacting with their environment".
For an organism to survive in a certain ecosystem, the ecosystem must provide a certain amount of basics:
1) Food: The ecosystem must provide edible substance to the organism, whether as plants, other animals, or a way to get nutrients.
2) Water: Of course, there are plants and animals that can survive long time without water. However, water is a key component to the survivability of the organism.
3) Shelter: Most animals must have a long-term shelter against the weather. Shelter also provides protection against predators.
4) A way to reproduce: Whether an animal reproduces asexually or sexually, the organism must have a way to keep the population alive. Remember that the disappearance of an organism can greatly affect the food chain & web, and can lead to the destruction of the ecosystem.
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