What are the characteristics of animals?

There are many kinds of animals, but they all have certain characteristics. All members of the animal kingdom are food-dependent creatures. In order to survive, they must eat plants or other animals. All animals have sensory organs. Because of frequent activities, animals have a nervous system directly controlled by them, and many animals have a circulatory system to help them inhale oxygen, absorb nutrients and excrete waste. Scientists divide them into subfamilies and subgenus according to the same physical characteristics, and the whole animal kingdom is divided into two categories: animals without backbones are called invertebrates; Spiny animals are called vertebrates.