A characteristic of living things that distinguishes them from nonliving things is that only living things:

• A. Are made up of cells
• B. Move actively at all times
• C. Have a nervous system
• D. Can photosynthesize without chlorophyll

Answer: (A)

Cellular organization is what sets living things apart from nonliving things. Every known living organism is made up of cells, from single-celled bacteria to complex multicellular beings. Cells are the basic units that carry out life processes like energy use, growth, and reproduction, so this structure is a defining feature of life. Nonliving things don’t have organized cells performing those processes.

Movement at all times isn’t universal—many living things, like plants, don’t move actively, and some nonliving objects can move only because something else pushes or pulls them. A nervous system isn’t present in all living things (plants, fungi, and many microorganisms lack one). Photosynthesis without chlorophyll isn’t a universal trait either; while some organisms use pigments other than chlorophyll, not all living things photosynthesize. So the statement about being made up of cells best identifies what distinguishes living things.