Both animals and plants grow. Why do we say that growth and differentiation in plants are open and not so in animals? Does this statement hold true for sponges also?
The growth of a plant can be said to be indeterminate. This is because a part of a plant can grow infinitely, i.e. always growing and forming new organs to replace the older ones. This is not the case for animals. Animal growth is limited and stops after a certain age when they get mature. This is why one can say that the growth and differentiation in plants and animals are different.The sponges can be said to be an exception in the animal kingdom. This is because they are the animals which show a cellular level of organisation. They depict the characteristics of open-ended growth but cannot be called one since they cannot grow beyond a certain size.