Animals - The main organs are: brain, heart, lungs, liver, kidney, stomach and intestines. While there are others pretty relevant, the mentioned organs are strictly needed for surviving. These organs behave as a whole, performing different and complementary functions. The brain is the driver of their performance. Through its environmental interpration, it sends chemicals (neurohormones) to modulate the physiology of organs. In order to work together, the organs need to be conected, and to have a constant communication. This conection is achieved through blood vessels, artheries, veins and capillaries. The mean of comunication is blood, and the constant flow is provided by the heart pumping blood continuosly. Through blood nutrientes, and chemical messengers travel and inform the organs how to modulate its activity. --------Plants - Plants do not have organs, nor vessels, artheries, etc. as animals do, but they do have tissues, and a complex system to transport water nutrientes, called xylem and phloem. This system is pretty important to transport nutrients made in leaves (by photosynthesis) through the entire plant, and also water absorbed form the roots.