Grade 9 Biology Unit 5 : Human Health, Nutrition, and Disease

Unit 5 of your Grade 9 Biology course is called “Human Health, Nutrition, and Disease.” In this unit, you will learn how the food you eat, your daily habits, and your knowledge of diseases can help you live a longer and healthier life.

First, Chapter 5.1 explains what food is and why it’s important—not just for energy but also for body growth, repair, and overall well-being. In Chapter 5.2, you’ll learn what nutrition means and how your body uses food to stay healthy and active.

Chapter 5.3 introduces the seven major food groups: carbohydrates, proteins, fats, vitamins, minerals, water, and fiber. You’ll discover their functions, sources, and the health problems that come from not getting enough of each.

In Chapter 5.4, you’ll learn what a balanced diet looks like. You’ll also see how food needs can change depending on your age, gender, activity level, and special conditions like pregnancy.

Chapter 5.5 explores deficiency diseases such as rickets, goiter, and anemia. You’ll understand how missing nutrients can lead to serious health problems and how to prevent them through better diets.

In Chapter 5.6, you’ll study malnutrition in both forms—undernutrition and overnutrition. You’ll learn how to measure body health using Body Mass Index (BMI) and understand its role in public health.

Chapter 5.7 focuses on substance abuse. You’ll learn how drugs like alcohol, tobacco, khat, and cannabis affect the brain, heart, liver, and lungs. This chapter also explains addiction, withdrawal, and the social and health effects of drug use.

Chapters 5.8 and 5.9 introduce infectious and non-infectious diseases. In Chapter 5.8, you’ll study diseases caused by bacteria, viruses, and parasites—like HIV/AIDS, tuberculosis, malaria, and COVID-19—and learn how they spread. In Chapter 5.9, you’ll discover non-infectious diseases such as diabetes, cancer, hypertension, and sickle cell anemia, and how lifestyle choices and genetics play a role.

By the end of Unit 5, you’ll be able to explain what good health means, identify the nutrients your body needs, recognize common diseases, and take steps to protect your health and your community.

To help you reach these goals, the course includes quick notes, clear diagrams, national-exam-style questions, and examples from real life in Ethiopia. These will help you prepare step by step for classroom tests and the national exam.