This document discusses various life processes in living organisms. It describes the criteria for determining if something is alive as movement without external help. The main life processes that help maintain life are nutrition, respiration, transportation, and excretion. Nutrition involves taking in food, respiration is the breakdown of food using oxygen to release energy. Transportation moves food, oxygen, water and waste throughout the body, while excretion removes waste. The document explains these processes in plants, animals and humans.