organs are composed of one or more types of
An organ is a unit composed of several tissue types. Outline. Organs are structures composed of two or more primary tissue types arranged in various proportions and pattern to perform a certain function or a range of functions. The lung is one example of an organ made up of all the four primary tissue types. The tissues that make up the lung function collectively to expand in order to draw air from the atmosphere, exchange oxygen in inhaled air with carbon dioxide from blood, eliminate/give off carbon dioxide and deliver oxygen to blood.