The animal kingdom has the most diverse and most number of species in the world. In as much as the animal kingdom is so diverse, one of their major characteristics is that they rely on other animals and plant for feeding and they are also mobile.
Most animals carry out their reproductions sexually and also have organs that enable them to see, touch, feel, hear, taste and smell.most of these are made of cells in millions , based on their function, these millions of cells can be divided into tissues.
Because the animal kingdom is so broad, it is now subdivided into other categories, which is now Also also further divided. This subdivision are based on the the animals characteristics on similar ground.
The presence of absence of backbone is one of the most common way to divide the animal kingdom. Animals such as fish, birds, and mammals are called vertebrates, and invertebrates animals suck as insects lack backbone.
This is to explain that the animal kingdom is vast and have endless elaborations.