There are many important life functions or processes, necessary to keep a single cell or a complex organism alive. Respiration is important because it allows chemical energy from glucose to be converted to ATP to provide energy for life processes. Excretion is important to remove wastes, including carbon dioxide, excess water, nitrogenous wastes and excess salt. Excretion allows a living thing to maintain homeostasis. Synthesis is important because cells must be able to manufacture necessary components or chemicals essential to life. Examples are the synthesis of proteins such as hormones, enzymes and structural parts needed by cells. Transport is the life process that allows the passage of materials inside and out of cells, as well as the circulation of materials around the cell or organism. The larger the organism, the more complex the transport system is. A human has a heart(muscular pump), arteries, veins and capillaries, that allow materials to move around the body to and from the cells. Other life processes include, digestion, reproduction, immunity, locomotion, coordination. All except reproduction are necessary for an individual's survival. Reproduction is necessary for the continuation or survival of the entire species, rather than an individual.