psychologicalblogspot

 All living organisms are made up of cells. Unicellular organisms consist of a single cell that performs all basic functions. In multicellular organisms, there are millions of specialized cells. Specialized cells in multicellular organisms carry out specific functions efficiently. Different groups of cells are responsible for different specialized functions. Muscle cells in humans contract and relax for movement, nerve cells carry messages, and blood transports oxygen, food, hormones, and waste materials. In plants, vascular tissues conduct food and water throughout the plant. Multi-cellular organisms exhibit division of labor, where specific functions are carried out by clusters of cells in a definite place in the body. These clusters of cells are called tissues. Tissues are arranged and designed to maximize efficiency in performing their functions. Examples of tissues include blood, phloem, and muscle. A tissue is formed by a group of cells that are similar in structure and/or wo...