posted by Erica on .
One of the five charateristics of living things is being able to reproduce. Do all living things have to have all charateristics? Mules are living things and most are sterile. (I have heard of a few cases where a mule has given birth.) What about women who are sterile, they are living too.
Soap bubbles can divide and in essence reproduce. It's only when you take all 5 of your characteristics of life that you eliminate non-living. Even then, there are grey areas. For example, certain microscopic animals can dry up and encyst. In this state they have almost no characteristics of life. However, if it rains, they re-hydrate and come back to full status of life. So the question is, were they alive when in the suspended animation state? I think so. Sometimes rules are not as absolute as we'd like them to be. Biology is full of many shades of grey when it comes to definitions and categories.