An ecosystem is a ____ of living organisms (biotic) and the non-living (____) factors of their environment. Ecosystems can be of any size, but usually they are specific places such as a forest, a lake or a desert. There are two main types of ecosystems: natural and ____. A natural ecosystem is one that occurs naturally in an area. For example, a pond or a forest. An artificial ecosystem is one that is created by humans. For example, an aquarium or a garden. In an ecosystem, there are different types of organisms with different roles. ____ are animals that eat plants, ____ are animals that eat other animals, and ____ are animals that eat both plants and animals. ____ are organisms that make their own food, usually through photosynthesis. ____ are organisms that eat other organisms for energy. Ecosystems can change over time due to natural events such as fires or ____, or due to human activities such as ____ or pollution. It is important to protect and preserve ecosystems because they provide many benefits to humans, including clean air, clean water, and resources such as food and medicine.

Ecosystems

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