* Lack of Chlorophyll: Plants have chlorophyll, a green pigment that captures sunlight and uses it to convert carbon dioxide and water into sugars through photosynthesis. Animals lack chlorophyll and cannot perform photosynthesis.
* Different Metabolic Processes: Plants are autotrophs, meaning they can produce their own food. Animals are heterotrophs, meaning they need to consume other organisms (plants or animals) to obtain energy and nutrients.
* Digestive Systems: Animals have digestive systems designed to break down and absorb pre-existing organic compounds from their food. They lack the complex mechanisms that plants use to manufacture their own food.
Therefore, animals depend on external sources for their food and are classified as consumers in the food chain.