Animals are eukaryotic, multicellular organisms that live on land, sea, or air. They breathe oxygen and consume organic materials, and are capable of sexual reproduction. As members of the biological kingdom Animalia, they have a variety of functions that distinguish them from other types of organisms. This article discusses some of the different types of animals and their classification. Listed below are some of the more common examples of animal life.
Animals are categorized by their organ systems. Their systems are highly complex and diverse, including a nervous system, digestive system, and circulatory system. The latter is responsible for carrying oxygen and nutrients to cells throughout the body. In addition to the organs, animals also have a musculoskeletal system, which helps them move and reproduce. Unlike plants, which use their organs to maintain their bodies, animals have many systems to perform essential tasks.
Animals are classified by their physical features. They must have multicellular bodies, which is the main distinction between them and human beings. This makes them different from other forms of life. They are multicellular and have internal membranes. These cells help the animals to move, digest food internally, and have sensory systems. Unlike invertebrates, these animals have no protection. Their only defense is that they are living and are not infected by harmful substances.