Living Things are structures that are composed of one or more living cells. They might either be whole organisms (like dogs or pine trees) or components of such whole living organisms (like noses, tails, and pine needles). The healthy leg of a living person is a living thing (as is the person), but an amputated leg is not. Almost every living thing is either capable of biological reproduction itself or has components which are capable of biological reproduction (such as the cells in a living arm). Red blood cells are abnormal living things in that they cannot reproduce.