Explanation: All living things are made of cells, use energy, respond to stimuli, grow and reproduce, and maintain homeostasis. All living things consist of one or more cells. Cells are the basic units of structure and function of living organisms. ... All living things can sense and respond to stimuli in their environment. In biology, an organism is any living system (such as animal, plant, fungus, or micro-organism). In at least some form, all organisms are capable of response to stimuli, reproduction, growth and development, and maintenance of homeostasis as a stable whole.