Living things reproduce, grow, adapt to the environment, respond to stimuli and metabolize. They also undergo homeostasis, collect and convert nutrients, and use energy. Living things are organized into one or more cells. The five groups of living things are the animal, plant, monera, protista and fungi kingdoms.
Living things reproduce either sexually or asexually, resulting in new organisms. Homeostasis allows living things to maintain a steady state of their internal environments, such as temperature and electrolyte concentration. The cell is the fundamental unit of life, and cells are organized into tissues, organs and organ systems. The cells of living things differ in function and structure, but they all have genetic material, which determines their characteristics. Algae and plants utilize energy from the sun to make their own food during photosynthesis. Other living things obtain energy from food substances during metabolism.
Living things store surplus energy in form of chemical compounds, such as fats and carbohydrates for later use. Life processes, such as digestion, absorption, excretion and assimilation, are common to most living things. The growth of living things occurs in an organized pattern and involves changes in size and shape and maturity of body parts to perform adult functions. The development of simple living things, such as amoeba and bacteria, is relatively limited. Complex organisms, such as animals, have a complicated process of development. Living things are able to move, but some, such as plants, have a limited power of movement.