A tissue is a cluster of cells that are specialized to perform a particular function. Examples include blood tissue, phloem tissue in plants, and muscle tissue.

Division of labour refers to the specialization of cells to perform specific functions, with different groups of cells dedicated to different tasks, leading to increased efficiency in multicellular organisms.

Muscle cells contract and relax for movement, nerve cells transmit messages, and blood cells transport oxygen, food, hormones, and waste materials.

Specialized cells in multicellular organisms efficiently perform specific functions, allowing the organism as a whole to carry out complex tasks more effectively.

Amoeba is an example of a unicellular organism. It carries out movement, intake of food, gaseous exchange, and excretion within a single cell.