Dear Student, Various life processes essential for life are Nutrition, Respiration, Circulation, Reproduction and Excretion. Nutrition is the process of assimilation of food and using it for growth of organism. Respiration is the process of using oxygen to produce energy from food. Circulation of blood is the process of transport of nutrients and oxygen to all tissues of body. Reproduction is the process of production of offsprings from parents for continuity of life. Excretion is the process of elimination of metabolic waste from body. Regards