Autotrophic Nutrition
Autotrophic organisms are able to synthesize their own food using simple inorganic substances like carbon dioxide and water. This process is known as photosynthesis, which involves capturing sunlight energy and converting it into chemical energy. Plants, algae, and some bacteria are examples of autotrophs.

Key points:
- Autotrophs are self-sustaining organisms.
- They produce their own food through photosynthesis.
- They are the base of the food chain.

Heterotrophic Nutrition
Heterotrophic organisms, on the other hand, cannot produce their own food and rely on other organisms for their nutrition. They obtain organic substances by consuming other living organisms or their byproducts. Animals, fungi, and some bacteria are examples of heterotrophs.

Key points:
- Heterotrophs depend on other organisms for their food.
- They consume organic substances for energy.
- They are at higher trophic levels in the food chain.
In conclusion, animals are heterotrophs as they rely on other organisms for their nutrition, while plants are autotrophs as they can produce their own food through photosynthesis. Both types of nutrition play a crucial role in the ecosystem, sustaining life and maintaining a balance in nature.

Animals are heterotrophs.