Protecting animals

Why should we protect animals that are on the brink of extinction? For instance, plants produce the oxygen that we need to breathe. The life of a plant relies on pollen carried by insects and minerals found in animal carcasses. In other words, the earth has many life forms whose lives depend on one another. This is called biodiversity. When an animal or other life form becomes extinct, it breaks its link with other life forms, and threatens our lives as well.