Characteristics and Requirements of Life
All living organisms display key characteristics of life. These include movement (changing position), responsiveness (reacting to changes), growth, and reproduction. Additional characteristics are respiration (obtaining oxygen and releasing energy), digestion, absorption, circulation, assimilation, and excretion.
Life depends on five critical environmental factors. Water is the most abundant substance in your body, essential for metabolic processes, transport, and temperature regulation. Food supplies necessary nutrients, energy, and raw materials for building body structures.
Oxygen makes up about one-fifth of air and is vital for releasing energy from nutrients. Heat affects the rate of metabolic reactions, and pressure (both atmospheric and hydrostatic) is important for breathing and blood circulation.
Quick tip: Think of your body as a complex machine that needs the right inputs (water, food, oxygen) and conditions (heat, pressure) to function properly!