Answer:
Animalia.
Explanation:
Biological system of classification was explained by Carols Linnaeus. He explained the system of classification and explains the different level of classification to classify the organism.
The animals are made of the different body parts and they are heterotrophic organism means that they cannot prepare their own food. The kingdom animalia was further classified on the basis whether they have the backbone ( chordata) and without the backbone ( non chordata).
Thus, the answer is kingdom animalia.
