Science Grade 4 Chapter 1 Lesson 1 – 3 Completed definitions for Life Processes: 1. cell – the basic unit that makes up living things. 2. life process – a function that a living thing performs to stay alive and reproduce. 3. organ – a part of an organism that performs a specific function. 4. organism – any living thing that can carry out life processes on its own. 5. organ system – a group of organs that work together to carry out life processes. 6. reproduce – to make more living things of its own kind. 7. tissue – a group of similar cells that work together. 8. chlorophyll – a green material that helps plants make food and gives leaves their color. 9. leaf – the part of the plant that uses sunlight and air to help the plant make food. 10. photosynthesis – the process plants use to make food. 11. root – the part of the plant that takes in water and nutrients from the ground. 12. seed – an undeveloped plant sealed in a protective coating. 13. stem – the part of the plant that carries water and nutrients to and from the root and leaves.