Mold is a simple, microscopic organism, present everywhere, indoors and outdoors. Mold is a fungi and is needed to break down the environment. For mold to grow and reproduce, it needs only one food source of organic material, such as leaves, wood, paper, and moisture. Mold grows by digesting the organic material, gradually destroying whatever they grow on. Mold growth on surfaces can often be seen in the form of discoloration, frequently green, brown, gray, and black. Mold releases countless tiny, lightweight spores, which travel through the air.