Why does animals cannot make their own food?

This is incorrect, while some animals cannot make their own food, many animals can make their own food.

Animals that can make their own food are called autotrophs, which includes plants, algae, and some bacteria. These organisms use the process of photosynthesis to convert sunlight, water, and carbon dioxide into glucose, which they use for energy.

Animals that cannot make their own food are called heterotrophs, and include animals like humans, insects, and birds. Heterotrophs must consume other organisms, either plants or other animals, to obtain energy.