A "Living Thing" refers to any organism that exhibits the characteristics of life, such as growth, reproduction, and response to stimuli. This category includes a wide variety of entities, from tiny bacteria to large whales. Living things can be classified into two main groups: plants and animals. Living things are made up of cells, which are the basic units of life. They require energy to survive, often obtained through processes like photosynthesis in plants or eating in animals. All living organisms interact with their environment and adapt to changes, ensuring their survival and continuation of their species.