THE PROCESS OF NUTRITION

the animal kingdom is so huge and varied that it is very difficult to summarise how the different processes are carried out.

• All animals need take food from their environment, all animals need to process the food in order to extract the nutrition elements. The processing of food takes place in the digestive system. Animal digestive system iis made up of a length of tube whish the food runs throught and in whish the food is transformed. Birds and mammals have a more complex digestive system than invertebrates whose system is much more simple or even not-exist, as in the case of sponges.

• Animals also need to take oxygen from their environment, animals have a variety of differents respirator organs fish and many aquatic invertebretes have gills, insects have small tubes called trachea, and amphibeans, reptiles and mammals have lungs.

• all animals need a system for transporting the substances they need to survive to the cells this is called circulatory sistem its more conplicate in the vertebretes than that of invertebrates.
• finally all animals have an excretory system whish clean the blood and eliminates waste products.