1. Multicellularity and Heterotrophy: Animals are multicellular eukaryotes, meaning they are composed of many cells with a nucleus. They are also heterotrophs, meaning they obtain their nutrition by consuming other organisms, unlike plants which produce their own food through photosynthesis.
2. Movement and Locomotion: Animals are generally motile, meaning they can move independently and actively. This ability allows them to search for food, mates, and escape from predators. While some animals may be sessile (attached) at certain stages of their life, they have a mobile phase in their life cycle.
3. Nervous System and Sensory Organs: Animals possess a specialized nervous system that allows them to respond to stimuli in their environment. This includes the ability to perceive and process information through sensory organs like eyes, ears, and touch receptors. This enables them to navigate, communicate, and learn, making them highly adaptable and diverse.
It's important to note that these features are not absolute; there are exceptions and nuances within the animal kingdom. However, these characteristics generally distinguish animals from other life forms.