How animals are formed

Here we will stop only to describe that the cells that develop animals are generally very small-it would take several thousand of them to gauge an inch, to make sure that they can not be seen without a microscopic lense- which numerous millions or billions of them might be required to make the body of a solitary pet. The most basic of all pets might have only a single cell. Numerous are bloodsuckers, which means they can not live by themselves, yet need to live in the bodies of other animals, or in plants.