MRS GREN
MRS GREN is a memory tool used in Biology to describe the seven essential life processes that all living organisms must carry out. These processes help living things survive, grow, and reproduce.
1. Movement
All living organisms show movement. Animals move their whole bodies, while plants move parts like leaves, stems, or flowers. Movement helps organisms find food, escape danger, and grow towards light.
2. Respiration
Respiration is the process of releasing energy from food. This energy is needed for every activity, including growth, repair, and movement. Plants and animals both respire.
3. Sensitivity
Living things can sense changes in their environment and respond to them. Animals use sense organs (eyes, ears, skin), while plants respond to light, gravity, and touch.
4. Growth
All living organisms increase in size and develop new structures. Growth happens through cell division. For example, a seed grows into a plant, and a baby grows into an adult.
5. Reproduction
Reproduction allows living things to produce offspring and continue their species. This can be sexual reproduction (two parents) or asexual reproduction (one parent).
6. Excretion
Living organisms produce waste substances, and they must remove them. Humans remove carbon dioxide, urine, and sweat. Plants remove oxygen and carbon dioxide.
7. Nutrition
Living things need food for energy and growth. Animals take in food by eating, while plants make their own food by photosynthesis.