That each of our neatly packaged and very intelligent human organisms is a separate entity, a separate being. But this packaged organic body of ours is a system that works only in concert with an infinite number of internal and external relationships with other systems. These systems can be living or non-living, organic or inorganic. These systems produce and consume food or energy. Some produce oxygen, some carbon dioxide.
Some systems take care of our wastes.
Some clean our water and air. We do not really have a thorough grasp, thorough understanding of the complexity of our bodies. The land as an organism is even more complex because it involves many organisms all intersecting, all interrelating, all producing and consuming, cleaning and excreting, breathing and eating. But the land is an organism. The only thing missing is skin.