UNIT OVERVIEW

This revision covers the four big topics from Term 2:

1. Photosynthesis – how plants make food using light
2. Animal Nutrition – how mammals get, digest, and use food
3. Gaseous Exchange – how organisms get oxygen and remove carbon dioxide
4. Excretion – how the body removes waste products

These topics connect to each other. Plants make glucose through photosynthesis. Animals eat plants (or other animals) to get that energy. Both plants and animals use oxygen to release energy from glucose (cellular respiration). The waste products from these processes must be removed.

What you should be able to do after revising:

• Explain photosynthesis and what affects its rate
• Describe how food moves through the human digestive system
• Compare how different organisms exchange gases
• Explain how kidneys filter blood and control water balance
• Interpret graphs, tables, and experimental data

What you already know from earlier grades:

• Cell structure and organelles (Grade 10)
• Enzymes and how they work (Grade 10)
• Basic organ systems (Grade 9)

---